Screenrant answered it pretty well:
Earth 89: Tim Burton's Batman Movies
Tim Burton's Batman films are represented in one quick cameo, which confirmed it as Earth-89. Danny Elfman's familiar Batman ...
From Crisis: Episode 2 (Batwoman)
Legends of Tomorrow have retired and Mick Rory is left inhabiting the Waverider
Batman (Kevin Conroy) has retired and can only move thanks to an ...
So I want to know how much should I know from Arrowverse before jumping into Batwoman?
At present (Oct 2019), Batwoman has no crossover or involvement with the rest of the Arrowverse that you need to ...