[alphabettsy]

The older batteries were rated for 500 cycles so that doesn’t seem unusual.

[rahkiin]

Except 80% is regarded as pretty much EOL, and this is a 2017 model.

[fomine3]

Apple is too late to implement battery protection feature (limit max charging%) for always AC connected machine. It's implemented in 2019 meanwhile 2000s ThinkPads supported that.