I went down that road before, it's how I started at Proton. I ended up with an .io TLD, which now has an uncertain future. Right now, I'm not too invested in it and I'm not sure I want to invest further in a TLD that could rug pull me in 10 years. I just spent several hours looking for a semi-decent .com (and to some extent .net/.org) I could live with and it's rough out there. Everything is being squatted on.
If I can find something, I'm not sure I want to stick with Proton. Their growth into new apps has felt pushy and spammy, there is a degree of lock-in where their apps are required (or a bridge), and search isn't the best. I was looking at Fastmail if I do make the jump, but that all hinges on finding a better domain situation I can live with for the next several decades. I think my current Proton subscription renews in December, so I should probably act now if I'm going to do something.
The unlimited aliases are kind of a gift and a curse. I always thought having a unique email for each site would be great, to figure out who is selling my info. However, keeping track of every address I gave out was tedious, and out of the 40 or so I did it for, I don't think I ever ran into an issue (which is good)... so it was a lot of work for little to no payoff. I did see that my adobe email got out there from using a +alias with Gmail years ago. With the new features that were added to Gmail and Proton to highlight newsletters and easily kill them, I was able to dramatically cleanup my inbox pretty quickly about a year ago. Though I suspect they just made a rule behind the scenes and didn't kill them at the source, which would be my preference.
With email, I do question if it's worth it. Even the privacy stuff that companies like Proton talk about... it's mostly marketing. Gmail controls a majority of email. When emailing anyone using Gmail, Google is still getting the email. The protections only exist if emailing Proton to Proton, which I've never done.
So it's hard... but is it worth it? That's a question I struggle with. I prefer my experience in Kagi to Google Search, and I like supporting a business model where I'm the customer instead of the product, but is my life materially better than someone who isn't up at 3:30am thinking about this stuff? My quiet rebellion feels insignificant.
I'm feeling like the guy in the middle right now, and have felt that way for many years now... https://imgflip.com/i/b329ok