In my experience, for seniors it's a conversation about past experience, deep dive on a selected project/technical problem of candidate's choosing, and sometimes some quizzing on the technologies the candidate claims to particularly experienced in, that are of interest for the company. For juniors, it's quite often coding something very simple (non-algorithmic, no gotchas) in an IDE to verify if the candidate really has experience with the stack they claim to have.

I've been interviewed in dozens of places and the only leetcoding/whiteboarding I've experienced was in American corps (Google, Palantir), in Sony games division (which from what I've heard is arguably an American company) and in one wannabe-cool startup in London that paid shit anyway. Nobody I know in Europe grinds algorithms in their free time...

Depends on the company (and country). At least here in Stockholm (SE) take home coding assignments and/or whiteboard problem solving seems pretty common for both junior and senior positions.