Apparently the debug profiling from a week ago worked and I just looked in the wrong spot. Also did one today while it was happening and attached them both.
I'm also having this issue, without the visual lag. Probably nothing to do with villages since there isn't one at spawn. I attached a link to a video showing what happens. Forgot to press F3 + L and I will next time this happens. Very annoying bug that fixes itself after a few minutes. Nothing lags the spawn chunks. My base is partially in them but nothing that creates lag is. (Base is underground) Before I started recording, I had died and sent to spawn, but the only chunks that were loading were the ones in the green barrier, which shows the central spawn chunks where entity processing can take place. After about 30 seconds they loaded and 10 seconds after that I started recording. Not sure how many people experience this, but it is VERY annoying. Also, sometimes when I go through my nether portal (In lazy spawn chunks (no entity processing)) the game freezes for a few minutes. It starts on the loading screen, freezing on "loading terrain". After a couple minutes wait, the game loads, but I can see through a most blocks. A few minutes after that, the game fully loads and runs normally.
(Video was too big to fit in the attachments)
IMPORTANT EDIT: It seems that F3 + L doesn't work while the game is in this state
EDIT 2: I made a copy of my world to see what happened in creative. I can confirm that commands don't work when the game does this either. It also doesn't take up any more computing power than normal while broken.
edit 3: added a screenshot. The world is basically unplayable now as the bug won't fix itself anymore. I've sat for an hour just hoping that the game would somehow fix itself but it won't.
development: may have something to do with particles. on the profile I did earlier today before the rest of the world loaded (I was arriving to spawn through nether portal), a huge amount of bubble elevator particles were visible. After I decided to try and turn off particles and see if that helped. When I came back through nether portal, everything loaded fine. I need to test this more because I was only gone from spawn chunks for about 30 minutes.