I'm hoping the RAR5 implementation will be finished soon, as PS5 releases will start to use RAR5 (https://www.srrdb.com/release/details/Official.PS5.Release.Standards.v1.0-2021)
However, the project seems to be in a bit of limbo, with the official repository still being MIA (http://rescene.wikidot.com/forum/t-13564168/solved-bitbucket-org-gfy-pyrescene-down) and the developer basically archiving the source (https://twitter.com/pyrescene/status/1307763952911298562). No clear yes/no on whether or not development is ceased was given though, although there seems to have been no activity since.
I really wonder if the project is being continued somewhere.