No I mean that if in Brave I say "add this page to the home", the launcher gives an error

Ah, pages like in webpages. Gotcha.

It’s interesting, Lawnchair works totally fine with these “app action” 1×1 widgets, and Firefox can add website shortcuts without any problem for me. I’ll try it in Brave a bit later.

That's strange, that hasn't happened to me. Maybe a reinstall might fix the problem? I use it on a Pixel 8A