ASUS RT-AX53U AX1800 Non-U Support

Hey all,

I've been looking for OpenWRT compatible routers in India, and I stumbled across ASUS RT-AX53U (AX1800).

On looking at the OpenWRT page (https://openwrt.org/toh/asus/rt-ax53u)for the device, there's a warning:

Warning! The RT-AX1800U and RT-AX1800 (non U), aren't the same device, don't attempt to flash non U devices

Even tho the page has a warning of non U variant, the OEM homepage URL redirects to the Asus' 1800 non U page and on the Amazon page, and on few threads, the comments I found say the router supports OpenWRT. The product pages of both the sites are almost similar, with only minor differences,

Has anyone flashed the non-U with OpenWRT?

Links to the Asus page:

Can you guys also suggest other routers that would support OpenWRT available in India?

AX1800 means 2-antenna 2.4+5GHz router, RT-AX1800U and RT-AX53U are the trade names of one of such units.
Another (+1 LAN port) is RT-AX54 (no U here) with multitude of market stampings.