If you like Pidgin I'd recommend https://gajim.org/ - it has a similar feel to the UI, is cross-platform and actively developed. Use it with a modern up-to-date server (see https://joinjabber.org/ for some general advice, and https://compliance.conversations.im/ for testing a specific server).

Gajim is undergoing a UI redesign right now that will make it unlike Pidgin, and with a single window only.