Why did I lose achievements?

The variants achievements, other than 960, could only be received from playing them on the Play server. KotH was removed from the Play server so apparently the achievements were also removed

The other variants, other than 960, are going to be removed from Play as well at some point, so those will likely be removed as well

I got the "Higher Ground" and "Mountain Climber" award this summer by playing King of the hill tournaments. So it was possible to get this achievement (at least very recently). I also got the other variant awards, except 4 player chess, the same way this summer.

👍

KotH was removed from Play a little over a week ago

What was the reason for it? I find exactly this variant quite useful.

https://www.chess.com/announcements/view/heads-up-chess-variants-are-moving-to-chess-com-variants

2 more achievements have been removed

what are they

first! and battle royale

Gamification is part of the science of keeping people engaged with websites/media. Stop being suckers and giving away parts of your life for made-up busywork. If you want an achievement, and it is something you are already doing anyway, that's one thing. If you are doing every achievement even if they are drudgery for you, then you are being exploited, plain and simple. See a therapist about your need to be a completionist...or watch this video:

It’s just a fun thing to collect, we aren’t philosophical nerd 🤓

Au contraire.

And 8 MORE achievements have been removed

Total number of achievements: 136 to 144 to 145 to 137 to 133 to 131 to 123

Yes. This time the 3 Check and Crazyhouse groups got lost:
Easy as 1-2-3
Three Strikes
3Check games
3Check rating
Surprise!
Mad Scientist
Crazyhouse games
Crazyhouse rating

Yup

The maximum achievements possible to get now are 123