I played them both: Yakuza 1 in December/January, emulated on PC and mostly streamed to my couch on either my NVIDIA Shield or my tablet. I thought it held up really well except for the brief on-rails shooting portion towards the end. So far it's been my favorite in the series because it has English voice acting. I was surprised to see that apparently Sega stopped dubbing the series because of criticism: kinda sucks I don't have the option on most of the games now.
I played Yakuza 2 in February, and I had the Deck at that point. It ran perfectly, no issues. I wish it was dub'd, but that's my only real complaint. I'm not sure if a game can have too much content, but if so Yakuza 2 is where the series starts to approach that. In Yakuza 1 I was able to do most of the things naturally just by alternating between main story beats and side content. In Yakuza 2 and 3, it feels like I could spend a hundred hours or more on each game and still not finish it all. If I wanted to play just 1 or 2 games a year that would be fine, but I've got other things to do so I just focused on the stories.