I can recommend the TP-Link Archer MR200
(that you linked to before), as I have that one myself!
It also has 2 excellent 4G antennae, which will probably pick up a much better 4G signal than a smartphone (I can't get 4G on my phone indoors or even most places outside, but this modem does) or a 4G USB Dongle for that matter. Also, you could always attach an external outdoor antenna (e.g. Solwise 4G Omni-Directional Outdoor Antenna
) later on if needed, to boost the signal further. Plus, it has built-in WiFi and 4 Ethernet ports, so you can connect your PC & printer to it direct, or via Powerline adapters. I have mine in an upstairs window (for best signal), and connect it to my network downstairs via powerline adapters/plugs.
Also, with that router (and some others), you can "force" it into 4G LTE mode, which is useful in areas with a weak signal (as in where I live!), as otherwise "Auto" mode will usually drop to a slow 2G or 3G connection.
So - I can certainly vouch for that router, yes it is quite expensive but I find it very flexible and it does the job well fore me at least.
(Admittedly, I keep my slow ADSL Max connection as it has unlimited data, and have an expensive DrayTek Vigor 2860Vac
router that I use to "Load Balance" my ADSL link with the 4G connection coming from the TP-Link Archer MR200 router, which provides a good link plus backup in case either ADSL line or 4G connection goes down).
You can get USB "4G Dongles" (unlocked ones are around £50, e.g. Huawei E3372
) that can be used in conjunction with existing routers *if* they have USB ports *and* support a 3G/4G connection via USB (I don't think, looking at the specs, that the Netgear DGND3700
router you mentioned does?) - but the dongles are less flexible, and don't have the more sensitive external 4G antennae that dedicated 4G routers have, or built-in Ethernet ports (although some 4G dongles have connectors for external 4G antennae).
One other option I've come across, where you can share the 4G link from a smartphone with your router, is via a service called Boosty
, although I don't know much about it personally (I have seen a review of it here: Boosty Review
Personally, based on my own experience so far, I would probably recommend the purpose-designed 4G Router (and, on personal experience, the TP-Link Archer MR200 is what I have, and has been excellent for me, so far), in spite of the £100 cost.
I hope this helps a bit anyway - other forum members may hopefully provide further information & advice.