I'm not about to switch away from signal, it's still one of the most privacy focused apps out there. And from a privacy vs UX perspective probably still the best app on the market.
Anyway, usual recommendations for signal alternatives: Conversations (XMPP), Wire, Briar (uses Tor, no desktop version), and if you don't care about being open source/free software there is also Threema.
A lot of those alternative's usability depends on your needs and expectations.
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