You're supporting exactly one browser - the one you use and switched your dad over to (at least for this one activity of mushroom picking)?

My comment is in general for my apps. As I said, for my mushrooming app I'm using a native app.

Are they that different since it’s basically just chrome reskins and Firefox?

And Firefox is 3% of the browser market, and god knows what fraction of the mobile browser market. You only need to worry about Chrome and Safari.

This depends on your user base: their age, their country, etc.

If someone with a cheap Xiaomi with a weird default browser comes and tells me that they have an issue with my app/game, I can't get back to them and tell them to fck off because they are not respecting the stats. Or rather, I definitely could but I don't want to.

I'm typing this from a cheap Xiaomi. You're good to go. (Default browser seems to be Chrome, though I use brave)

Yep, they are mostly similar but not exactly the same.

I developed a small web-based game and even that one required quite a bit of testing and debugging from players' reports as it seems every manufacturer uses a different default browser.

I have a check specifically for UC Browser (had no idea of its existence) as it has a bug regarding dates. Go figure.

And then people downvote me because they think all is Chrome and Firefox, while that's not the whole picture at all.

For an informational static page, it's almost surely going to work on all major browsers out of the box.