Endless issues with this server. (TPS stuck on Loading; Failed to synchronize registry data from server; Server taking way longer than it should to load)

I've made several posts for each issue I've had with the server, the first one being the problem with the TPS getting stuck on "Loading ..." when he server gets up, and not being able to join it even though it's finished starting up.

I've already sent this in a comment on my first post, but I don't think that's being checked by moderators anymore, so maybe it should be a new post. There are some different problems occurring anyway.

After completely remaking the modlist, knocking it down to 20 (fairly light) mods, the TPS "loading" is still an issue. The server takes twice as much time to load than it did with twice as many mods, and when it does the TPS will get stuck on "Loading ..." for a long while. I genuinely think there might be a bit more to this issue than the server being overloaded.

I understand that Aternos is constantly being updated behind the scenes so it's entirely possible this is a new issue, but in years of using Aternos I've never seen this specific problem, no matter how many mods there have been. I've tried changing forge versions around, and going back to a previous version of the world before adding mods but for some reason this server is really struggling. I don't understand which mods could possibly be causing so many issues. We currently play on two different aternos servers together, and the other one is heavily modded, and trust me that one has had it's issues, but the non-stop struggles with this particular server is insane. I'm starting to think that there is just something inherently wrong deep within this server, like it's cursed not to work. Or like at some point somewhere one of the mods or something has leaked deep into odd folders, making the server unthinkably unstable.

Obviously this time it closed itself before it managed to get up but here's one of the latest logs: https://mclo.gs/h4CyIqy

The last time I managed to get the server up, the TPS was stuck loading and I couldn't join as it was still loading according to the client. It eventually said the server was online and the TPS was 20, but then it "Failed to synchronize registry data from server" so I couldn't join. (This is unrelated to the last time I had this same problem with the old modlist, which I fixed by enabling the macaw's fences mod on the client)

The time before that the server restarted itself - not closed itself, restarted. Then it closed itself because it took too long to load.

This is the most recent server log, when the server managed to actually get up: https://mclo.gs/m9v3Fz6

I don't know if it's useful at all to send logs from moments the server did and didn't manage to get up, but either way here they are.

Here's also the latest client log: https://mclo.gs/aCB5v0R from trying to join the server.

All the mods are the same and I've deleted the config folders from both the server and client, but maybe I missed something, or maybe something was sneakily removed by curseforge like last time.

I really need help with discovering what's causing the weird infinite TPS loading issue, and why it's struggling so much with these mods. I've been working on trying to get mods working on this server for so so many days.

Quote from Roman

You're bombing everyone with a ton of information no one wants to know and no one needs to know. And no one wants to read through your book of historic problems.

Just explain what your CURRENT problem is and share the latest log. Please be as short and precise as possible and that all-important information is included.

The current problems are the TPS getting stuck on "loading ..." for a while after the server loads up, the "Failed to synchronize registry data from server" error when joining the server (again), and finding out what's causing the server taking too long to load despite no obvious resource-hogging mods.

This is the latest server (from when it last managed to load): https://mclo.gs/m9v3Fz6 and client log: https://mclo.gs/aCB5v0R

I'm not including these problems as past problems I've had with the server, but current on-going/reoccurring issues. I'm asking for help in finding out why this server in particular has had these sudden problems, when other - seemingly more overloaded - servers I've set up on Aternos run without these issues, which is why I included as much context and information as possible. If you need any of that context you can read the original post.

Quote from Roman

Remove the mods one by one from your server.

Every time you remove a mod from your server, you need to restart it, then check if the problem still occurs.

If the problem doesn't occur anymore, know that it was probably due to the modification you last removed.

Does the server need all the same mods as the client for the client to join? After removing mods from the server and not touching the client it says mismatched mods, however for as long as I can remember, the client has always been able to have extra mods installed, as long as it has the mods the server has as well

Edit: I feel like that sounds very confusing, essentially I removed all the mods from the server and tried joining to make sure it was working at all. The client is still modded, however. When I tried joining it couldn't because of the mismatched modlist. When working with mods in the past, the client has always been allowed to join - no matter what additional mods they had installed - as long as the mods the client had installed included all of the mods installed on the server. Is this different now, or is there a different reason I'm getting this error?