For those interested to know on dd-wrt usage.
I have DIR-880L with DD-WRT and setup as repeater bridge on 5Ghz (aka backhaul like).
Main router is DIR-868 A1 on stock firmware
So far the experience is very stable no issues, with around 15 devices connected to it (wired lan, 2Ghz, 5Ghz).
My personal benchmark is video call (e.g. facetime), there is no lag or cut-off. So is good for my usage
Using:
Firmware: DD-WRT v3.0-r36698M std (08/22/18)
Time: 14:38:02 up 7 days, 19:08, load average: 0.00, 0.00, 0.00