Apparently this issue has plagued Realms for quite a while. I'll explain exactly what I've done to try to remedy these steps:

1. Let Java and all versions of it have full privilege through my firewall (which is just Windows Defender, I have nothing else).
2. Reinstall Minecraft: Java Edition and the launcher via deleting the entire .minecraft folder and uninstalling the launcher through Windows. I did this 3 times.
3. A full network reset via Windows settings
4. All of the steps listed in the MC-227913 bug report (which is not resolved).
5. Installed multiple different JDK versions, namely 16 and 17.
6. Viewed the log file located in %appdata%/.minecraft/logs (was not helpful, I guess it doesn't log connection issues?)
7. Used a HTTPS sniffer (namely Fiddler) to no avail (it doesn't hook properly to Minecraft for whatever reason).
8. Tested to make sure this is an issue isolated to Realms via trying to connect to various classic multiplayer servers.
9. Tested via a mobile hotspot, USB tethering, a VPN, and a wireless connection.

This issue has persisted throughout, I'll check this bug report daily if I'm not automatically emailed as I'd love to cooperate to find a solution, since I'm really interested in playing with some of my buddies, and I'm sure y'all never want to see this issue be posted ever again 🤣