There is a broswer extension called SquareX, that allows us to have "Disposable" broswer tabs. This basically means that the browser tab itself runs in the cloud, which is more or less the perfect secure and private way to do anything in the Internet.
But as a free service it has pretty big limitations, most importantly related to the quality.
I think if Proton can offer a similar service with thier paid VPN plans, but with offering at least stable 1080p 60fps quality, that could elevate the entire service to another level compared to the competition.
Ofc i have only very little idea of how hard it would be to integrate this into the existing service, but i definetly would pay a bit premium for that feature.