The anti-glare is definitely worth it and it’s also very noticeable outside. The other option is that you could just upgrade the screen from ifixit if you’re also going to be upgrading your storage anyways.
All versions of the deck allow you to upgrade the SSD. There’s actually a lot more vendors selling 2230 nvme drives now. I’d recommend staying away from SABRENT Rocket since their support is nonexistent and they also have a high failure rate. The Corsair MP600 mini and Micron 2400 is a better option.
For me the game still isn’t “fine.” It’s a lot more stable now but even with a completely fresh install and save I’m still running into a lot of the problems that was present during launch like all the civilians looking the same regardless of the setting you’re on, NPCs running into each other and then choking up sections of the map. I just keep running into these NPC blobs where they just stand there and do nothing. There’s still things they said they fixed like npcs materializing out of nowhere.