>>4766507PayPal doesn't care if you do your work with a private or business account. They also don't give a shit if you do your taxes or not. It's up to you if you want to upgrade. It's not mandatory. Business just adds some helpful features.
That 10k number you have there is the largest sum you can receive in one transaction with a private account. I don't think it will force upgrade you to business if you try to go over that number.
If you run an online shop, a business account will be very helpful. If you just do commissions and maybe run a Patreon, a private account will be enough.