Neither one is suitable to run SQM at gigabit rates.
My early testing with the Archer C7v2 seems to be limited to ~330 mbps NAT/route only, even with software flow offload. I need to confirm that I enabled s/w flow offload properly. I don’t have a MediaTek MT7621AT to measure. However, you might want to read the related
Edit: Looks like s/w flow offload iswas broken on master. See further
Edit: 2019-10-04 -- Appears to have since been resolved on master. Untested at this time.