Literally just search on MRM, there's only a few doujin for SBR >>2702258
Supposedly she's just consolidating everything on her website, which is fair, but it's really hard to get access to as a non-japanese speaker. She briefly had a lot up on BLand but I dunno if they're still up and none of it was her current work. It really sucks bc Marion is my favorite artist. I wish I could just sub to a patreon or similar for her work.