If you want the "better" router for gaming and VPNs, OpenWrt wins. If you want the highest possible Ookla Speedtest number, stick with stock.
Is custom firmware better for the Archer AX10? archer ax10 custom firmware better
If you find a random .bin file on a Russian forum claiming to be "DD-WRT for AX10," do not flash it. You will brick your router. If you want the "better" router for gaming