There are about 5dcb between them at full speed , on paper the gammaxx is the loudest simply because it has the highest rated fan speeds but in reality you could limit it to 1200rpm & it will still do the job fine.
The 212 on paper is quiet but ive used half a dozen & the supplied fan does not have any longetivity , after 6 months if the bearings start to give they get noisy.
The cryorig is the best cooler , no doubt about it.
If you can get one at the right price then fine.
Here in the uk though the gammaxx is £25 , the cryorig h7 is £45.
No way on this planet its worth £20 than the gammaxx at all.
There's about 2c & 2-3 decibels between them at best.