So, hypothetically, let’s say that a single animator solo KA’d an entire episode (unlikely, I know) and all of it happens to be top notch.
I understand the rule of not uploading entire episodes, but if it’s a ‘Solo Ka’, then do we actually post the episode (minus the op and ed), or put it into portions depending on the circumstance of the sakuga?

I don't think this type of scenario has ever happened nor that it will due to the nature of solo KA eps, but to answer your question yes, it would be split up into multiple posts depending on the scenes and context. Although the closest thing to your scenario are solo OPs/EDs, sometimes those are be uploaded in full, for ex. https://www.sakugabooru.com/post?tags=ryouma_ebata+source%3A*solo*ka But again it varies from case to case.

There is actually a good number of solo KA episodes out there, here https://www.sakugabooru.com/post?tags=azur_lane_%28tv%29+source%3A%2304+ for example or https://www.sakugabooru.com/post?tags=mushoku_tensei%3A_isekai_ittara_honki_dasu++source%3A%2305+ etc)

Due to the nature of the booru, uploading an entire episode would make little sense.
Its a tool that is used to watch generally "short" clips/scenes, that focus on a certain aspect of animation, either effects, character acting, etc. not 20 minutes of multiple type of animations.
So yeah splitting in "short" scene is definetly how it need to be done.