I bought 2 pairs of the game changers but have not used them yet. For whatever reason I am terrified of my oven like Kevin in home alone is afraid of the furnace, which doesn't make any sense since I am 34 and live in a studio apartment. FP has massage guns as well for very cheap.
I had the exact same fear. Sat there watching my oven for 8 minutes while they cooked in there. It was fine. The insoles are meant for this, so put your fears aside and throw them in the oven... at the right temperature and for the correct amount of time. You'll be fine.
As for the massage guns, I have been meaning to get a massage gun forever. I had the exact same thought as you, saw it on their website for not too expensive, but still was able to find a cheaper one on amazon that works fine. I hate amazon and am angry at myself for getting it from there but the deal was too good ($86 for the gun and 6 head replacements). If you want to support footprint, it looks like their guns are good, but you could probably find a cheaper bundle elsewhere. But definitely get one. It has helped my recovery time so much.
Lastly, I finally got to skate with my gamechagers (3mm) in a pair of NB 440's. At first it was very weird. I've never worn orthotic insolex let alone skate with some. After an hour or so of skating in them, I got used to them. My lower back didnt hurt as much while skating. The soles of my feet didn't randomly cramp up or become sore. It is a real "game changer" but definitely an adjustment. They were also in a fresh pair of 440's so that didn't help the stiffness but eventually it all felt right.