It does seem unlikely Plex would include this ever. Hate their generic pivot to ad supported bs. But as a lifetime sub to Plex I’m riding it down.
I hear jellyfin supports plugins which is one step easier.
At home I watch on an Apple TV with a nas running isponsorblock. Works well but is a single device/location solution. And I am still paying for YouTube premium.
Got the fork of prowlarr you recommended up and running but getting a timeout on adding ABB. Will try again later. For now, it is working in jackett again so that is a good temp solution. I will ideally have both running so there is a backup if one goes down later.