For me personally simplest /most bang for buck is hammer curls with fat gripz.
Saying all that, at your stage I would just make sure you focus on progression and training hard and heavy on back day with primary moves like dumbell rows for 5x5. This will build overall upper body size as well as a base of arm mass
Or roofing labourer! Cutting a 10 meter piece of galvanised iron with tin snips will give you massive forearm burn and pump. My old boss had the most humongous forearms and hands I’ve ever seen… Twas hilarious cos he wasn’t a big bloke and his upper arms where terrible lacking
I wish I could do those. maybe if I can find some dumb bells for cheap I can incorporate them. Maybe i can do some variation by pinching plates and walking. not the same thing but if its tough it might work
There is a difference between working on your grip strength and actually trying to make your forearms larger. No question there is overlap but still there is a difference. Since you mentioned that you are unhappy with your “11 inch forearms” I will assume you want more size.
If you want to make your forearms larger stick to writs curls, both front and reverse. I like holding dumbbells over a bench first with palms up and then I repeat with palms down. I work a higher rep sequence as the forearm have smaller muscles and they are slow twitch. I feel more of an isolation than when I perform barbell wrist curls. One more exercise I recommend for larger forearms is reverse curls with a straight bar. Again, work higher reps and plenty of sets.