yes, it's capable. All Teltonika's RUT have built-in option with fail-over feature in RutOS, so it's available in whatever version of device you choose.
However, I'm not so sure about Starlink unit, how do you connect to it? In most devices you have only 1-WAN 100Mb/s Ethernet port and 4G LTE modem as alternative Cellular interface. So no other option to have WLAN as other WAN to be connected to it.
Generally speaking, you should take into account other factors, like: your individual needs, how much performance device should be capable to handle (quantity of RAM/CPU, type of LTE modem/supported WiFi version & performance, available ports etc.) and budget spend on buying device.
Take a look at Teltonika's webpage and some comparisons.