Is my starter motor on the way out?

Jumped in my 09 Jimny this morning. Turned the key and nothing. Lights don't dim. Can hear a whirring like perhaps a fuel pump. Nothing else.

Came back to it this afternoon, checked power between the insulated terminal on top of the starter motor and the battery negative, 12.5v there. Tried to start again, this time with the bonnet up and stood outside the car and can hear the solenoid clicking. Tried a few more times and it turned over slowly and started. Been for a drive. Turned it off an on a few times (while facing downhill to bump it if needed), no issue at all.

I didn't hear the solenoid this morning, but not sure if I would sat in the car with windows up and bonnet down.

Is this likely to be the starter motor on the way out? Anything else I might check in-situ?

Is the starter motor the pig to change it appears to be from its location?

Thanks for any advice.

It sounds like battery to me.

I would check the main battery earth as I had the same issue with mine a month ago and replaced the starter and it was still the same and found poor main battery connection

There is a small spade connector on the underside of the starter motor. Check the connection is good.