Synapse via ESS Community (https://element.io/server-suite/community), as it just works and is trivial to update, and tracks the best practices from Element in running a deployment with all the Matrix 2.0 stuff (sliding sync, OIDC auth, Element Call) enabled. The Helm charts are literally the same underlying codebase that powers ESS Pro for folks like NATO and the UN; the only difference is that ESS Community doesn't have the horizontal scaling and enterprise-privileging features that ESS Pro has.

The only gotcha is that Synapse is still not very resource efficient, especially for disk space, although work is finally under way to solve that.

(Meanwhile all our customer deployments run Synapse Pro + ESS Pro in order to get the scalability and Rust worker implementations in Syn Pro.)

I self host a Conduwuit (or Continuwuity or whatever the active fork is named these days - I just git pull periodically).

Mostly use it for following some OSS projects that operate on Matrix, and I also decided to use it for some low severity notifications for job results while mobile. It works well enough.

Matrix clients still largely suck though Element X has finally gotten better over the past year.