I have another option to consider if you are in for a really new and experimental support. I just submitited the first attempt to support the ZyXEL NR7101: http://lists.openwrt.org/pipermail/openwrt-devel/2021-April/034777.html
This is an outdoor router built as a MIMO panel antenna, based on the well supported MT7621 SoC and a Quectel RG502Q-EA modem (pretty much the same as RM500Q, but in an LGA package soldered to the mainboard. Placing the whole router outdoors avoids long antenna cables and makes it easy to have a larger number of antennas. You'll get much better signals with such a setup.
I haven't created an OpenWrt device page for it yet, but see for the vendors info: https://www.zyxel.com/products_services/5G-New-Radio-Outdoor-Router-NR7101/
The device is obviously insanely expensive... But so are good antennas.
But don't go for this yet unless you are familiar with running bleeding edge OpenWrt. Some fiddling will be required. You might need to hook up a console to install OpenWrt if you get an NR7101 with a locked bootloader and all management access disabled (i.e recycled ISP branded device). But the NR7101 is very easy to open without breaking anything, and the console header is already soldered. So if you have a USB TTL UART device then it's just plug and play.