What is the best device to use to set up a 2 meter remote base using allstar node

I have a UHF repeater and would like to set up a 2 Meter remote base to link to a single
simplex Frequency. Would it be best to use the RTCM as a node as the link from the repeater?
Or do i need use a RPI computer with an interface on the remote base as well as the repeater or do i use an RTCM on both the repeater and the remote base?

The RTCM can not interface to two radios. You’d need one for the remote and one for the repeater. A computer is needed as the RTCM is a peripheral device (not a node). The computer need not be colocated with the RTCM(s).

A single Raspberry Pi or other computer could interface to both the remote and the repeater via any peripheral… you can mix and match peripheral devices.