If you want an ordinary WiFi router for indoor use, with an internal 4G modem for primary or backup WAN, then the MF286D is the perfect choice. If you already have the indoor WiFi router and want to connect it to a 4G/5G modem with antennas mounted outdoors for optimal signal, then consider the NR7101.
In the second situation, please also consider plugging a Huawei E3372 into a USB port of your existing router. It would be much cheaper while still allowing external antennas.
If you get the E3372h variant of the modem you have the following options:
- Use it as it is: it will be visible as an Ethernet card, function as a NAT router with quite low number of supported concurrent TCP flows, but will also handle reconnections without any OpenWrt specific bugs.
- Reflash it to the stick (21.x) firmware using balong-flash: the modem will speak NCM then. You get rid of one NAT layer this way and potentially get a public IP if your network provider offers it. The lack of NAT on the modem also reduces the attack surface - note that the modem is running a 12+ years old unpatched kernel, so it can matter. But then the OpenWrt-specific lack of the reconnection feature will bite you.