Hello all,
I think iv found a mixup in the hex values with the fuse settings for an ATtiny1614 in Atmel studio 7 and what the datasheet says.
Datasheet: DS40001893B
Fuse settings for SYSCFG0 with Bits: RSTPINCFG[1:0]: states that setting only bit 3 (0x08) sets reset pin for UPDI. Here is a screen shot: