Hello - is it going to be OK to travel to TPE then connect with ~1.5-2h transit time to a Starlux flight to SGN (on separate itineraries)?

Are there any issues using mobile check-in for a mobile boarding pass as an American citizen with travel originating in Taipei heading to Vietnam? Will any passport checks or even check-in procedures happen at the gate if need be? Just want to see whether everything can go smoothly airside, or if for whatever reason, one is required to leave/exit and check-in which might make timing tight.

Thank you in advance.