an update. bought the 5g modem (ee variant of zyxel nr5103e) + rm68 sim. made full use of it since 2 weeks ago.

so far so good👍

yes, yes and yes

another variant is by 3. another user say the 3 variant has slightly different firmware with more settings available for advance users. but at the time of purchase i have no knowledge of this.

so i just bought the cheaper one out of the two (less rm60)

the modem is pretty much plug and play. put ur sim in. name ur SSID/password and ur good to go.