Sure, there is very little distinction. I'd argue that both are donations. Pay-as-much-as-you-want (if $0 is an allowable price) represents a donation with a slightly different funnel.
The for-profit vs non-profit distinction is immaterial to me; the distinction is between actually paying for products (e.g. buying an ingame item or support or a subscription or whatever; some sort of 'contractual' thing), and literally giving money away with no strings attached.
Google's particular funding model for their App Store is a different kettle of fish entirely - they can decide that apps beginning with the letter A pay a 90% fee and that's just how it works.
To purely play devil's advocate, there are a number of 'home restaurants' (operate out of my home) that are pay-what-you-want and operate quite profitably. I believe 100% they should be taxed (i'm totally conflating taxes and apple/google profit share but it's a form of a network fee?).
Through this discussion I do wish there was an exception for FOSS for individuals at a legal level.
I can 100% agree though that the fees which google/apple charge are extortionist.
But again, what is FOSS with a donation link vs free-to-use software with pay-as-much-as-you-want.
One sounds like a non-profit while the other sounds like a for-profit.
Perhaps if you can directly show your software is FOSS via licensing etc that there should be a special exemption?
Seems like there needs to be a sole-proprietier non-profit... but man that seems like rife for abuse.