Sekiro Achievements bugged

Edit: Seems like it will probably fix itself eventually, according to other peoples experiences. Thanks for the replies.

About an hour ago, I completed all achievements on Sekiro, but a few of the last achievements didn't register. Here is exactly what happened: I beat a boss that should have given me three achievements at once, one for beating that boss, one for beating all
bosses and one for getting that particular ending. If I had actually gotten these achievements, I would now only have two achivements left, one for unlocking all "skills" and one for unlocking all other achievements in the game. After seeing that I didn't
get the achievements I looked up similar problems on some other forum page and found that sometimes there is a delay.

I then saw that I had games updating in my queue and I don't know how this works but I thought that maybe this is what was causing the delay so I waited for these updates to finish. While doing that I saw that the download speed varies greatly, sometimes
being at a good speed and sometimes dropping down completely so that it doesn't even show the number anymore. Also a couple of times it even said something like "installation paused" for like a second before starting again. NOTE: Despite this, the xbox NEVER
said that I was disconnected from xbox live, I am 100% sure of that. Also, I have seen the up and down behaviour of my wifi speed before, it seems like it always does that, at least when downloading on xbox.

Anyway, after these updates were done I continued playing and got the achievement for unlocking all skills, hoping that that would trigger the others as well. It did not trigger the others but I did get that one, so now I have 4 achievements left in the
game.

After that I have looked up the official ways to solve this problem and I have tried restarting the console several times in different ways, including waiting for the power supply to turn off. I have looked at my achievements both on the console and on xbox.com
and on both it's as if I haven't done the achievements at all, it does NOT say "Done! Unlocking.". All I know about my gamerscore is that it is currently the same on my console as on xbox.com.

Also, this is probably not relevant but on the home menu, when waiting for the games to update I noticed that one of the windows that usually show some sort of information, now showed nothing except some text that said something like "not avaliable".

Could the problem be that my internet speed somehow tanked to zero exactly when I beat the boss, but recovered quickly enough not to kick me from xbox live? Xbox support also mentions waiting up to 72 hours for things to synchronize with xbox live, is that
something that has worked for other people with similar problems?

Also, since this apparently still happens to people after 14 years of xbox achievements, why isn't there some failsafe, like a way to manually make the console check game data for which achievements you have earned?

:)