> but a year or 2 ago the went back to OpenSSL for some reason which I did not fully understand.
That would be Void Linux [1]. One of the reasons iirc, is PEP 644 [2], in which CPython drops support for LibreSSL due to it not being fully compatible with OpenSSL 1.1.1 APIs.
That was either Void Linux (see sibling comment) or Alpine Linux.
You might also have read Gentoo Linux announcement (https://www.gentoo.org/support/news-items/2021-01-05-libress... ); technically doesn't fit your description since Gentoo never "switched" or "went back", but rather supported them simultaneously, and just pulled support for LibreSSL at some point.
IIRC, there was a Linux distro using LibreSSL, but a year or 2 ago the went back to OpenSSL for some reason which I did not fully understand.