About SuMo and USUM, I played both as they came out and thought it was really fun seeing the differences in story, from the middle on it becomes like two entirely different games, if you are a fan I would recommend both. If I had to choose, I would say USUM is the more complete game, has more content and side content, more story and even an interesting post game story that is definitely worth playing for any fan of the older games, and I am legit surprised seeing people talk about SuMo being preferred because my experience with everyone I talked about this has always been people preferring USUM.

About BDSP, biggest complaint is how they remade the old games but did not do almost anything new to it, didn't even add the extra story from platinum which makes platinum be a more complete experience than even these remakes. They're fine but underwhelming.

So if you only want one, I'd say USUM. If you are considering all and deciding on the order, I'd say SuMo, then BDSP to take a little break, and then back to USUM.