I worked for Virgin Media cable (way back when they used to be United Artists) and a regular gripe of the repair techs was that an installer had re-used the satellite TV cables internally which weren't up to spec and could cause poor reception.
If the cable is marked CT100, WC100 or WF100 it should be fine. Other spec cables may cause issues on longer runs.
Just buy screw on connectors, and they literally screw onto the cable, all you need is a sharp knife. Fitting guide
I wouldn't worry about the silicone grease unless its for an external fitting.
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