I added the forums to my “favorites”, which creates a button. I think iOS gives you other option to create short cuts that might be more direct than tapping the browser then tapping the favorite button.
2 taps vs 1 tap doesn’t bother me, so I haven’t bothered to figure out any other way.
Most browsers will let you do a “add to homepage” or “create shortcut” that will let you put a site in your home screen. In safari for iOS, tap the square with the arrow on it (middle of the screen, bottom on my phone) then scroll down and tap “add to home”