Yet "раб" is translated as "slave"..

In Bulgarian, a slave is „роб”.

Same with Polish, but in Czech where the word originates from, there is a difference and normal work is called "práce" not "robota" which is reserved for forced labor or as an in-jest name for work.

In Slovak, robota is apparently more like in Polish, it's commonly used to mean a job, sometimes as manual work, only historically for forced labour.

Russian isn't Czech and there are a lot of false cognates between the two.

These aren't false cognates though, they're actual cognates. Cognates can have different meanings. You might be thinking of 'false friends'.

My absolute favorite false cognate is 'arraigned' (English) vs. 'araignée' (French).

Arraignments would be far more nervewracking if they significantly involved spiders.

Interestingly, the Chernobyl liquidators forced to clean the roof were referred to as robots. I think the TV series expanded that to "bio robots", but books about the incident from tbe nineties simply used robot.

I like vonet and pachnout