Just an update from Ubuntu - for the upcoming release of Jammy (22.04 LTS targeting release in April 2022) we have started transition to OpenSSL 3 and currently upgrading to systemd v249. W.r.t. library choice usually GnuTLS APIs are nicer to use; however OpenSSL library tends to be the more performant one with more HW optimizations, and easier to certify. These two properties alone make me prefer OpenSSL whenever possible. Regards, Dimitri.