Buying a MT7621 router

[Borromini]

@1043Nv5

looks like MT7621 devices have switched to something called "DSA" which brings issues related to VLANs in LuCI. Would VLANs work via CLI? Any other issues I should be worried about?

All architectures will eventually switch to DSA (which has been introduced upstream in the Linux kernel). It should be able to do everything you can do with legacy OpenWrt swconfig today, but yes, LuCI isn't fully adapted to it yet. But on the CLI you can just configure it.

As for routing, you can use hardware offload with MT7621 AFAIK. That should increase the throughput numbers substantially. This topic may be very helpful to compare, however I see no MT7621 numbers with hardware or software offload enabled:

Comparative Throughput Testing Including NAT, SQM, WireGuard, and OpenVPN

Overview While there's been a lot of individuals testing various routers, the question still always seems to come up, "What can I expect from Router X?" I won't say that my testing is going to definitively answer those questions, but at least it should be a self-consistent data set. To be very clear, this is a benchmark. Like most benchmarks, the performance you get in your own environment may be different. If you have a craptastic ISP, a lossy ISP connection, a flakey cable, hosts pummeling y…

I am looking at the Gl.iNet GL-MV1000 (1 GHz dualcore ARM Cortex-A53, see topic above) myself, for an edge router without wireless.

@forests_gump

it has 1x Usb3, 1x Usb2, which allows you add-on a RTL8153 USB3 1000mbps to config it to a dual WAN

I would not recommend doing that. USB NICs should be considered a "better than nothing" solution, but not a worthy alternative. Better just reconfigure the internal port layout and borrow one of the LAN ports as a second WAN port. Should not be too much of an issue.