Questions on SNMP queries

We are currently using a LS300 modem with firmware ALEOS 4.4.5 and reading information from our software via SNMP.

We currently reading GPS information, temperature, power values successfully.

We need the cellular signal strength.
We are able to read the field RSSI correctly (1.3.6.1.4.1.20542.9.1.1.1.261.0)
If we read the networkServiceType (1.3.6.1.4.1.20542.9.1.1.1.264.0) it returns something like “EV-DO Rev B”.

My question is, if the networkServiceType is “LTE”, I suppose we need to read the RSRP instead.
We tried to read rsrp (1.3.6.1.4.1.20542.9.1.1.2.10210) but it returns an error. If the modem would be on an LTE network, would that node reply a value?

Also, how do we control what is called the “Relay Output 1” on the webpage via SNMP?
I can read digitalOutput1 (1.3.6.1.4.1.20542.9.1.10.1.859.0), but it always returns 0 no matter if I set the state to “OFF” or “Drive Active Low” via the webpage.