I cannot think of a single essential service I use on the Internet today which is ad funded. If it's essential I'm paying for it because the free, ad-funded version is shitty and unreliable.
We could ban Internet advertising tomorrow (give people time to migrate to paid services) and I genuinely don't think it would have much negative impact on society. Social media like Twitter and Meta would take a big hit and that would be very good for our society. Less teen girls would commit suicide, and less hate would be spread.
I'd start paying ten bucks a month or whatever for Google (already pay them a pretty penny for Workspace) and can't think of much else that I'd lose that would matter. Subscriptions to a couple sites of professional interest like Stack Overflow? Small price to pay for ending Internet ads.