after some time running router with openwrt and a stock asus router as a dumb ap, I moved on to two 1900acs where one is router and the other is dump ap (192.168.1.1 and .2).
Had a little trouble with both 5ghz wlans being enabled at the same time. Disabled 5ghz on router and it's now working fine from my dumb ap.
Router system log is being overloaded with
Tue May 4 19:07:57 2021 kern.warn kernel: [ 2820.185719] br-lan: received packet on lan1 with own address as source address (addr:60:38:e0:da:5a:be, vlan:0)
60:38:e0:da:5a:bF (read F) is router's 2.4ghz mac address. bE I don't know what is..
On the dumb ap I've bridged everything except switchport wan. I tried to bridge only eth0 and wireless network (both) but then I lost connection to the internet and my router. Dumb Ap is connected with network cable on lan port 1 I think back to my router.