Hi Gumps!
The only feedback I can offer is from my interview back in 2019, so it may have changed significantly since then.
The initial day consists of a group exercise (google einstein house puzzle) where they want to see you interact and adapt to other guys opinions. Usual stuff.
The second part will be a technical assessment in front of a panel where they'll ask you system/atpl/what-if situation questions.
If you pass through this, you will be invited to the sim the next day. Fairly straightforward, problem+ecam+dodar= great success.
I have a pdf file with some atpl questions they may throw at your way (they did with me, but I was non-rated).
Good luck!