Busking is not begging though and they don't advertise or try to sell you cds. If you give them money they'll appreciate it but they won't harass you if you don't (well there is always bad eggs but they aren't the majority).

There was an old guy playing violin all year even when it was super cold and I walked past him everyday and gave him some money. Not because he asked but because I wanted to. He was always appreciative and we both had a pleasurable experience.

I believe you can separate your business and private contributions by having an onlyfans link in your bio but not directly advertising it in your posts.
Kind of like I get paid as a software developer professionally but I still contribute to open source in my free time. Of course potential employers could go through my free stuff and then decide that they want to pay me to work for them, but it's not directly marketing my career for people not interested in it.