Since updating to 1.19 (I'm on 1.19.10 on PS4), I've found that generating new chunks while moving fast, such as with an elytra, is VERY slow. It affects elytra flight, so that (it seems) when a chunk can't load fast enough, my momentum just sort of stops mid flight, so even though I should be gliding up after gliding down - i.e. your basic elytra flight pattern - I still just remain gliding down though I'm pointing up. The player model in the top right seems to glitch out and flip to the side, and when that happens, no upward momentum can occur unless I use a rocket.

I've attached a video of a more severe case of chunk loading issue - this was after smacking into an unrendered mountain, since all I can see is blue sky even when looking down. You can also see the user model do the sideways movement that means upward momentum has stopped right at the start of the video, and at 30 seconds in. 

A related ticket is MCPE-156737, though it looks like that one is specifically for iOS.

FYI I do realize this ticket is mentioning both terrain generation time and elytra issues, but I believe they are linked. i.e. elytra momentum seems to stop when the game can't render the world fast enough. I had a similar ticket - MCPE-159601 - that was canceled due to mentioning 2 issues in one ticket, so I just wanted to address this so that this ticket isn't automatically closed.