Librewolf + arkenfox user.js maximum security profile will pass EFF and about every other test you could think of. The real problem is that security comes with cost to convinence. Multi session cookies and site history suck for security but are really convinent tools for browsing the modern internet.
Cookie clicker paid, stardew valley, Terraria, freedoom (gzdoom + open source IWAD packaged on fdroid store), mindustry, original peggle you can find apk on internet archive, opensurge, minetest engine with voxelibre game for open source minecraft.