I came in to Agatha All Along with no pre-conceived ideas or having done any looking in to the back story. So, it wasn't until I was deep in and watching Episode 6 (?) that I realized that it had a connection to the Marvel Cinematic Universe - WandaVision in particular. I felt scammed and peeved.
Well, having gotten engaged in Agatha All Along, I paused it and had to watch WandaVission. While WandaVision has some critical element as back story to Agatha All Along, it is pretty tangential (and - IMO - a much lesser show than Agatha All Along).
Well I finished E6, then dove in to E7-E9 and have to really give the show credit. The acting is superb across the board, with Hahn as Agatha being a standout. The sets have an off beat, original perspective as the show moves along. Most of all, the trials the characters go through and their growth is well done. The show keeps an engaging, adult story line, none of the usual sugar coating where everyone ends up ok in the end.
While I don't think the connection to the MCU was necessary, it is what it is. And, it does not detract unduly from the overall show. I would likely watch a season two if in the offing.