A lot of business owners I know who primarily use USD have this workflow:

1. Do USD books like normal, don't try to integrate BTC into them at all.

2. Establish a wallet or exchange account. As you spend or receive BTC, write it down somewhere so you can go back and figure out what a tx was for, if needed. This could be the memo field in the tx, a separate text document, whatever. Just like when you use USD.

3. At the end of the year when doing capital gains calculations, mark all "incoming" payments to that account as as Income. So that's all accounted for, easy. Likewise, mark all outgoing payments as "expenses" if they are valid business expenses. Most crypto tax calculator sites have ways to do this in bulk.

4. Make sure you record any transfers from one of your own wallets to yourself separately so they don't get tagged as capital gains events in step 3.

5. Whatever account software you use, open a support ticket with them and ask them to add BTC support. They need to hear from people that want this feature, or it'll never get added.