Frequently (but not constantly) the game fails to close its processes after exit.  This occurs when quitting via the in-game menus or via Cmd-Q.  The launcher will subsequently fail to open again until the processes are manually killed.  It does not appear to be linked to game version, but has occurred for me on multiple recent launcher versions.  This bug has been replicated on 3 different Macs in my household.

Example of processes left running:

ps aux | grep minecraft && ps aux | grep launcher
robert 83424 0.0 0.1 8830372 19720 ?? S 9:16PM 0:00.17 /Users/robert/Library/Application Support/minecraft/launcher/launcher.bundle/Contents/Frameworks/launcher-Helper (Renderer).app/Contents/MacOS/launcher-Helper (Renderer) --type=renderer --no-sandbox --log-file=/Users/robert/Library/Application Support/minecraft/launcher_cef_log.txt --field-trial-handle=1718379636,11638781105949175906,2159758163785498083,131072 --enable-features=CastMediaRouteProvider --lang=en-US --framework-dir-path=/Users/robert/Library/Application Support/minecraft/launcher/launcher.bundle/Contents/Frameworks/Chromium Embedded Framework.framework --main-bundle-path=/Users/robert/Library/Application Support/minecraft/launcher/launcher.bundle/Contents/Frameworks/launcher-Helper.app --log-file=/Users/robert/Library/Application Support/minecraft/launcher_cef_log.txt --log-severity=info --launcherui --num-raster-threads=2 --enable-zero-copy --enable-gpu-memory-buffer-compositor-resources --enable-main-frame-before-activation --renderer-client-id=5 --no-v8-untrusted-code-mitigations --shared-files
robert 83423 0.0 0.1 4587668 21076 ?? S 9:16PM 0:00.26 /Users/robert/Library/Application Support/minecraft/launcher/launcher.bundle/Contents/Frameworks/launcher-Helper.app/Contents/MacOS/launcher-Helper --type=utility --utility-sub-type=network.mojom.NetworkService --field-trial-handle=1718379636,11638781105949175906,2159758163785498083,131072 --enable-features=CastMediaRouteProvider --lang=en-US --service-sandbox-type=network --no-sandbox --use-mock-keychain --framework-dir-path=/Users/robert/Library/Application Support/minecraft/launcher/launcher.bundle/Contents/Frameworks/Chromium Embedded Framework.framework --main-bundle-path=/Users/robert/Library/Application Support/minecraft/launcher/launcher.bundle/Contents/Frameworks/launcher-Helper.app --log-file=/Users/robert/Library/Application Support/minecraft/launcher_cef_log.txt --log-severity=info --lang=en-US --launcherui --log-file=/Users/robert/Library/Application Support/minecraft/launcher_cef_log.txt --shared-files
robert 83421 0.0 0.2 4623864 25480 ?? S 9:16PM 0:02.23 /Users/robert/Library/Application Support/minecraft/launcher/launcher.bundle/Contents/Frameworks/launcher-Helper (GPU).app/Contents/MacOS/launcher-Helper (GPU) --type=gpu-process --field-trial-handle=1718379636,11638781105949175906,2159758163785498083,131072 --enable-features=CastMediaRouteProvider --no-sandbox --framework-dir-path=/Users/robert/Library/Application Support/minecraft/launcher/launcher.bundle/Contents/Frameworks/Chromium Embedded Framework.framework --main-bundle-path=/Users/robert/Library/Application Support/minecraft/launcher/launcher.bundle/Contents/Frameworks/launcher-Helper.app --log-file=/Users/robert/Library/Application Support/minecraft/launcher_cef_log.txt --log-severity=info --lang=en-US --launcherui --gpu-preferences=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 --log-file=/Users/robert/Library/Application Support/minecraft/launcher_cef_log.txt --shared-files
robert 98844 0.0 0.0 4269432 712 s000 R+ 8:05PM 0:00.00 grep --color=auto --exclude-dir=.bzr --exclude-dir=CVS --exclude-dir=.git --exclude-dir=.hg --exclude-dir=.svn minecraft
robert 83424 0.0 0.1 8830372 19720 ?? S 9:16PM 0:00.17 /Users/robert/Library/Application Support/minecraft/launcher/launcher.bundle/Contents/Frameworks/launcher-Helper (Renderer).app/Contents/MacOS/launcher-Helper (Renderer) --type=renderer --no-sandbox --log-file=/Users/robert/Library/Application Support/minecraft/launcher_cef_log.txt --field-trial-handle=1718379636,11638781105949175906,2159758163785498083,131072 --enable-features=CastMediaRouteProvider --lang=en-US --framework-dir-path=/Users/robert/Library/Application Support/minecraft/launcherlauncher.bundle/Contents/Frameworks/Chromium Embedded Framework.framework --main-bundle-path=/Users/robert/Library/Application Support/minecraft/launcher/launcher.bundle/Contents/Frameworks/launcher-Helper.app --log-file=/Users/robert/Library/Application Support/minecraft/launcher_cef_log.txt --log-severity=info --launcherui --num-raster-threads=2 --enable-zero-copy --enable-gpu-memory-buffer-compositor-resources --enable-main-frame-before-activation --renderer-client-id=5 --no-v8-untrusted-code-mitigations --shared-files
robert 83423 0.0 0.1 4587668 21076 ?? S 9:16PM 0:00.26 /Users/robert/Library/Application Support/minecraft/launcher/launcher.bundle/Contents/Frameworks/launcher-Helper.app/Contents/MacOS/launcher-Helper --type=utility --utility-sub-type=network.mojom.NetworkService --field-trial-handle=1718379636,11638781105949175906,2159758163785498083,131072 --enable-features=CastMediaRouteProvider --lang=en-US --service-sandbox-type=network --no-sandbox --use-mock-keychain --framework-dir-path=/Users/robert/Library/Application Support/minecraft/launcher/launche.bundle/Contents/Frameworks/Chromium Embedded Framework.framework --main-bundle-path=/Users/robert/Library/Application Support/minecraft/launcher/launcher.bundle/Contents/Frameworks/launcher-Helper.app --log-file=/Users/robert/Library/Application Support/minecraft/launcher_cef_log.txt --log-severity=info --lang=en-US --launcherui --log-file=/Users/robert/Library/Application Support/minecraft/launcher_cef_log.txt --shared-files
robert 83421 0.0 0.2 4623864 25480 ?? S 9:16PM 0:02.23 /Users/robert/Library/Application Support/minecraft/launcher/launcher.bundle/Contents/Frameworks/launcher-Helper (GPU).app/Contents/MacOS/launcher-Helper (GPU) --type=gpu-process --field-trial-handle=1718379636,11638781105949175906,2159758163785498083,131072 --enable-features=CastMediaRouteProvider --no-sandbox --framework-dir-path=/Users/robert/Library/Application Support/minecraft/launcher/launcher.bundle/Contents/Frameworks/Chromium Embedded Framework.framework --main-bundle-path=/Users/robert/Library/Application Support/minecraft/launcher/launcher.bundle/Contents/Frameworks/launcher-Helper.app --log-file=/Users/robert/Library/Application Support/minecraft/launcher_cef_log.txt --log-severity=info --lang=en-US --launcherui --gpu-preferences=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 --log-file=/Users/robert/Library/Application Support/minecraft/launcher_cef_log.txt --shared-files
robert 83414 0.0 0.3 5254260 52584 ?? S 9:16PM 2:14.38 /Applications/Minecraft.app/Contents/MacOS/launcher
robert 98846 0.0 0.0 4268408 700 s000 R+ 8:05PM 0:00.00 grep --color=auto --exclude-dir=.bzr --exclude-dir=CVS --exclude-dir=.git --exclude-dir=.hg --exclude-dir=.svn launcher