I ask because my experience with Neon has been completely different to what you just described. Ever since their 'closed beta' days, it has always 'just worked'. Their CLI has been great, none of my automation has ever bombed out without good reason, and I've never seen it cost me more than I expected. Notably, I was also able to self-host it with relative ease, and found that they actually encouraged people to do so. (In contrast, there are a number of similar 'open source' offerings such as Supabase that I've tried self-hosting, and found that while their core codebase is on GH, it is extremely difficult to deploy outside of their own environment. Not intended as a dig at Supabase, they do some really great work and contribute a ton back to the Postgres community - I'm just using them as a relevant example).
As an aside, I've also met people from Neon at various conferences, including co-founder Heikki. They all struck me as genuine Postgres enthusiasts & great fun to geek out with. Neon (like Supabase) have been _really_ pushing the envelope on Postgres for the last couple of years, and have sponsored some significant developments & proposals. In my view they're a 'real OSS company'. While that probably does rose-tint my view of them a little, that's important to me & makes me happier to give them my money. They've certainly done more for Postgres than AWS ever has.
There's also uBlock Origin, but I don't know if it's the largest adblocker yet. It should be, though. I think it is a serious competitor, even in terms of market share, to many major for-profit adblockers.