Tangential but I used Threads at a previous company and really liked it. I don't know how anyone could get a company that's already built around Slack to switch, but if you are starting fresh I think Threads offered a much nicer experience for async comms and especially for long discussions of consequence. Highly recommend giving it a shot!
$10/user/mo sounds expensive. And the free option looks so tiny it's a non starter.
I think both Slack and Threads should be a little more generous with their free packages. Maybe like 5 users and unlimited history or self hosted but no support.