Xbox vs Steam release (silly me)

Having just finished RDR2 for the first time, I decided that I would need to keep going and finish the story with RDR1. I had been playing RDR2 on my Steam Deck, and purchased RDR1 + “Undead Nightmare” for $50. Idk how I completely forgot, but I already own RDR1 as an Xbox 360 game, which I bought (without “Undead Nightmare”) for $10 several years ago. Steam allows refunds with less than 2 hours of playtime if done in within 14 days. Does anyone know if there are major changes between the Xbox 360 and Steam versions? I really want to play “Undead Nightmare,” but the pack is $50, and I saw it’s only 5-7 hours. What would you do in my position? Spend the money for the expansion and improved features, or save the money since the two versions are similar and the DLC is very short?