Question about Zyxel LTE3301 v4

The device has 2 SMA connections, so you can simply use antennas with SMA, e.g. this one: https://www.digitec.ch/de/s1/product/delock-ltehspagsm-antenne-2x-sma-stecker-mobilfunk-antenne-netzwerk-zubehoer-5833644.

But to be honest, you won't be happy with 5m cable. The longer the cable, the greater the attenuation of the cable, the less the antenna will do.

It would be better to go the other way, i.e. LTE3301 closer to the LTE source and then via LAN cable to the router / switch.

Or you can take the luxury route and buy an outdoor LTE modem Zyxel LTE7240.

Unfortunately, we do not know anything about this. In such a case, however, our suggestion would be to work with a repeater that can amplify the signal accordingly.