Help needed chosing a wire-only connected router

I'd like to buy an opensource based router
( to be connected to a tethered smartphone)
with an incoming usb port - for connecting the smartphone
and an outgoing USB port - to be connected to one laptop via USB cable
No wifi, no bluetooth
Just a plain good quality wire connected broadband router
operated by opensource firmware - with good record and oulook
for a long lasting support & updates
and a friendly GUI for an uninformed home user like myself
What do you suggest ?

It's a bit odd all that USB stuff...

Specifically, your router will have to act as a USB host for the purposes of connecting to the smartphone, but will have to act as a USB client when providing an internet service to the laptop.

A single USB bus won't be able to do both.

Might I suggest connecting to the router via ethernet and a USB gigabit ethernet adapter plugged into the laptop? With that config, you'd have a lot more likelihood of working.

I'd look at an RPi 4, commonly available, easy to replace, has a gigabit ethernet port and several USB host ports. Just turn the wifi and bluetooth off... You can install OpenWrt on it no problem.

The only thing I don't know about is what support OpenWrt has for tethered USB network interfaces to connect to the smartphone with... but I suspect someone will know that and can answer.

Here's a wiki page on tethering:

Check out GL-iNet.

Some inspiration: 72 devices with no wifi, but USB available, supported by recent OpenWrt, having sufficient ressources (flash+RAM) for future OpenWrt support

You can filter yourself for further criteria (e.g. number of USB ports).
Please mind that most of these devices are listed as Single Board Computer, which often come with no case.

If you drop the "no wifi" requirement, you will get 270 (!) devices more.
You'd probably be better off (in terms of cost and varietey to chose from) with chosing a device with wifi, and just not use it.

Which GL-iNet device is wired only?

None, but the OP wants to use tethering and gl-inet devices support that out of the box. They also run firmware based on OpenWrt.

Is the following router

suitable for the purpose i described in thia post ?

I think so. It has the one USB 2.0 port so the speeds will be limited by that USB 2.0 port, but the limits are a couple hundred megabits so it should be fine for most smartphone tethering purposes.

I do not have experience with this one: I only got GL-AR750. I know it is working fine and also less expensive. It does not have external antennas, so maybe more suitable for your use case.