I recommend the Banana Pi BPI-R3. Wifi 6 2.4 + 5GHz for wireless. 5 x 1GBe ethernet plus 2 x 2.5GB SFP for wired connections. Expansion with USB 3 and m.2 key M slot. 2GB RAM, 8GB emmc plus NAND and NOR flash if you want to use them, also a microSD slot. And it's a 4 core Arm 64 @ 2GHz. It's all Mediatek, which has traditionally been good at handling the nuts and bolts in hardware (and not offloading it onto the CPU). Very well supported in OpenWrt.
I highly recommend it. There are other more prefab AX arm routers out there, but not with the power and flexibility.