I did a 2 day long “bootcamp” for the company I now work at. Basically two days working directly alongside my future colleagues but on a non-product related exercise task. I really appreciated it. First day was still weird and I was nervous, but on the second day it already felt normal and all conversations were extremely relaxed.

I got involved in the daily team routine, took part in coffee talks, etc

Doing the actual task was just time filler for getting a feeling of the new workplace and for them to see if I fit in.

Especially thanks to the second day I knew I loved it there and that switching job will be the right move.

This was before Covid, though. Today this probably wouldn’t work anymore, with most people working from home and most meetings being remote anyway.

What I am saying is: it’s not just for the company that hires you, it’s also for yourself. Expecially if you have to quit another job first.