Welcome aboard!
Fishing that deep for me usually means vertical jigging no bobber, Just gotta know how much line you have out. Just takes practice. I have a few reels that 1 handle revolution is 30". Just turn backwards desired number of turns.

I jig for walleye at that depth on a regular basis, 8' Rod. two rod lengths on line, then 2 reverse cranks and I am at 21' start a bit shallower and work your way down.