Helmets!!!!

Various anti-fog products on market but one cheap way is to apply a little dish washing liquid on the inside surface, wait for it to dry and polish off with a soft cloth. Reapply as necessary once it wears off.

You could try a breath guard/deflector (do a search on Amazon) which Velcro’s into your helmet. Worked for my son but doesn’t work well if you wear glasses - just makes them mist up instead (don’t ask me how I know ?)

Pinlock system

You ever seen the scuba guys, right before they put their goggles on? spit on it and wipe it off, the saliva residue will keep it from fogging up.