How to activate 5ghz radio - WE1200

Hello everyone!

New Openwrt user here, so I'm still figuring out things, so go easy on me, please.

I have a CN repeater (Victure WE1200) (see FCC page below) which was quite unmanageable with its original firmware, so I decided to install Openwrt. I'm using it only for repeating WiFi, I don't need any fancy service or feature apart from that.
It is not listed in supported hardware directly (I know, I know, I shouldn't but...), but I figured out that it uses an MT7628 chip, then I just tried to flash an Openwrt firmware to see if works and it actually works!
Well, kinda...

I've uploaded the [mediatek_mt7628an-eval-board-initramfs-kernel.bin], then [mediatek_mt7628an-eval-board-squashfs-sysupgrade.bin].
I have full access (through SSH and LuCi), have tested the repeater feature and it's working flawlessly, but ONLY in 2.4ghz.
I've been searching in this forum how I can "turn on" the 5ghz and figured out the firmware didn't recognise the hardware.

I saw somewhere (in another device brand/model topic) that it could be a lack of a driver. This is the closest answer I got so far, but still didn't help me as I don't have any idea of which driver I should install to make it work.

It also could be anything else, basic or really advanced thing, I just don't have any idea.

Can someone help me with this?

Thanks in advance

why do you link to ad-laden site? official fcc site has original pdf-s
etron chip - 64MB ram
main chip - mediatek, solvent washed to no recognition
flash - blurred out or cut off
You need to take device apart and make good resolution board photos.

site is just an aggregator, links to official

I've opened earlier today:
chipsets: MT7268 (2.4ghz) MT7612EN (5ghz)
haven't check flash tho

drivers installed:
kmod-mac80211 - 5.15.150+6.1.24-3
kmod-mt76-core - 5.15.150+2023-09-11-f1e1e67d-1
kmod-mt7603 - 5.15.150+2023-09-11-f1e1e67d-1
kmod-mt76x02-common - 5.15.150+2023-09-11-f1e1e67d-1
kmod-mt76x2 - 5.15.150+2023-09-11-f1e1e67d-1
kmod-mt76x2-common - 5.15.150+2023-09-11-f1e1e67d-1

Anyone please?

Did you manage to boot OpenWRT even with degraded functionality? That would be huge leap to official support. Do lspci and cat /proc/mtd to get missing bits and shape the release.