I'm having troubles with my Phicomm K3 router: https://openwrt.org/toh/phicomm/phicomm_k3_a1
It works really well with 19.07.0 version in all areas except it's WAN->LAN routing performance is sub-optimal: I'm getting only ~500Mpbs of my 1gpbs link (no QoS, etc) where my other router (Netgear R6300V2 with FreshTomato 22019.4) is able to achieve ~940Mbps (with CTF enabled). I read the whole story about flow offloading and hardware NATs and was hoping that enabling 'software flow offloading' would help. However it seems to have no effect at all.
I tried to flash a forked version from here https://github.com/coolsnowwolf/lede which has 'Turbo ACC' options; those do not help either.
Any ideas how to fix this? I could assemble my own custom OpenWRT build if needed;