Receiving funds in the same address from a signature campaign is the most common option. However, even in the scenario that you mention, if you (as an entity) are well hidden behind the "takuma sato" persona, how will the person that you pay know who you are in real life? And, at the same time, why should they care?
Anyway, your point is important, so I get it. One user here (paid2 - I mention the name since he discussed it openly in another thread) does something clever, which is a good option to consider. I saw that BlackHatCoiner mentioned it above too. You can use a non-kyc exchange, like the one in my signature and exchange all the funds from your address into XMR. Then you can use the same exchange or any other that you want to exchange from XMR back to BTC (obviously using another BTC address). Don't forget to use Tor for this. You will make it impossible for the payee to imply that "takuma sato received X payments from a signature campaign and then used these funds to pay me".
Well just for reasonable privacy reasons. Suppose you pay someone with your signature earnings, you want to buy something from craiglist that is sold in exchange of btc, or pay for some service or something, and they google your address out of curiosity, now they find your apogio profile, and look up your political opinions, how knowledgeable you are on BTC, for how long you been involved and so follows. You get profiled. Anyone reasonable would not want that, so im just looking for ways to avoid this, without ending up in more trouble, like mixing the coins that end up tainted, paying with them and then being a target for that when the person that receives the coins says, "this dude I meet sent me these coins, go ask him". Chances are low but possible.
Your XMR may be interested to look at but man XMR is crashing so hard you may want to do that quickly. What I would like to know is a way to test your utxo before you send it into a KYC exchange, to know if they are tainted or not. Since we have no way to know where the coins that you recieve are comming from, it would be useful to run the utxo through some sort of database, like similar to haveibeenpwned website but for addresses, and this way one would make deposits and transactions with a better peace of mind.