I've used a hub to connect my USB A flash drive to my Android device before, but I prefer keep all of my ROMs on one of these USB C drive from Samsung:

https://www.amazon.com/SAMSUNG-Type-CTM-Transfers-Compatible-Waterproof/dp/B09WB2RPS4/ref=asc_df_B09WB2RPS4/?tag=hyprod-20&linkCode=df0&hvadid=598359365939&hvpos=&hvnetw=g&hvrand=3338694485576951648&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9012138&hvtargid=pla-1661254605787&th=1

They're tiny, copy is quick. Just make sure you use the correct file format. Some retro handhelds don't support exFat.

https://www.amazon.com/SAMSUNG-Type-CTM-Transfers-Compatible-Waterproof/dp/B09WB2RPS4?th=1

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This one is much faster than any of the sandisks. The speed performance alone is well worth it