if is paid by and for a 3rd party, is an ad. if not, is a tip.

That's not a good distinction. If I see an advert for Microsoft 365 in the Start menu on Windows they're both from Microsoft but it's still an advert.

It still would be a self promoting, which is still an ad.

six of one, half dozen of the other; it may not be a payed advertisement but it functions as one if it's suggesting products.

It's not like this is organic word of mouth we're dealing with here.