Hi yes the connector on the FP3 is a USBC the FP2 had a USB micro, so you had best get a new good quality cable, although any USBC may do ??
I cut the support to put the sim in the 3+
Cutting the SIM can work but you have to be careful as you may get it stuck in the slot. Some of the micro SIMS are slightly thicker too 
It will better to ask your network provider for a new nano SIM