I think the main thing to understand is that you need to know the cost basis of the sats you have in each wallet, regardless of where you bought them. When/if you ever sell, your cost basis of that sale will be based on the first sats in that wallet (FIFO). If those sats are a year or more old it's long term cap gains, if those sats are less than a year old it's short term cap gains.

The long and short of it is consolidate your sats into a few hardware wallets, know the basis of those sats in each wallet and hold them for at least a year before you spend them so the government fucks you less.

This whole thing sucks and these stupid IRS suits can go fuck themselves. Prison sucks though so I guess we have to follow this.