Im new to LLD and want to get involved after playing D2 for a long time.

Is lvl 30 classed as LLD?

Is there much demand for LLD on Europe Ladder servers?

If so, where is best for me to find players to pvp?

LLD are levels 9, 18, and 30. I can’t speak for Europe, but USEast has a good amount of active players.

Don't bother, it's very toxic.

in europe atm non ladder is more active (and possible will be hard to say about new ladder later)
most active bracket is 30 but sometimes we play 9 or 18 also
you can find most in games
non ladder - low lvl duel or 30vs30 or 30v30 or 30 vs 30
ladder - low duels or low lvl duels
smthnk like that