Golem is sadly terrible but that Gyarados card has potential. High HP for a stage 1 GX, the attack is very high cost but will OHKO almost anything. Babygyara exists as a one prizer that can hit 150 base in the lategame. No omega barrier unlike primal don but it has slightly better acceleration options. Having such a high colorless cost allows you to attach 2 DCEs if you're playing slow (dread storm can help stall for time) or do something cuhrayzee like including a kiawe and 5 fires in your deck for a potential second turn attack, something that groudon can't even think about.
The other thing with this card is it will have Lusamine for stadium recycling.