I too use ASUS RT-AX53U. Decent hardware. But stock firmware was terribly slow. IPv6 didn't even work.

I heard OpenWrt when I searched how to fix the stock firmware. Flashed it and never turned back. Now, OpenWrt is a critical infra in my house for adblocking, DoH, Firewall, Network Segmentation etc. None of these are possible with the stock firmware.