Out of those, application performance class is the one you want. Even better is a real-world random read benchmark.
The capacity standard isn’t super helpful. Everything from 64GB to 2TB is SDXC, which is supported.
The Steam Deck only uses UHS-I. It’ll work with UHS-II and UHS-III cards, but they won’t have any meaningful benefits.
Pretty much any decent microSD Card in 2023 is class 10. If it’s anything else, that’s a red flag.
Higher UHS speed class and video speed class are probably better, but they’re measuring write performance. For playing games, random read performance is far more important.
Out of those, application performance class is the one you want. Even better is a real-world random read benchmark.