Gentoo has USE flags to use gnutls+compat_layer rather than openssl. This is/was possible because they was a strong-ish push a decade ago by GNU aligned projects to force this down the throat of each package because OpenSSL had a problematic license exception deemed incompatible with GPL by some. The heathbleed fiasco helped this push. Then with LibreSSL, diversity survived a bit longer.
However, now that OpenSSL work to solve "all the problems" is starting to get into releases distribution actually can use (OpenSSL 1.1.1*) and will eventually be able use after extensive effort (OpenSSL 3), I don't think this support for TLS diversity will survive very long. The technical and licensing being solved, only the philosophical/political ones remain, which isn't enough for the large effort required to support multiple TLS libs.
However, now that OpenSSL work to solve "all the problems" is starting to get into releases distribution actually can use (OpenSSL 1.1.1*) and will eventually be able use after extensive effort (OpenSSL 3), I don't think this support for TLS diversity will survive very long. The technical and licensing being solved, only the philosophical/political ones remain, which isn't enough for the large effort required to support multiple TLS libs.