ATTiny414 inline assembly operand constraints for IO pin parameter
The ATTiny 1-series has the GPIO registers mapped outside of the io port register space, so they cannot be accessed using out or in. You will either need to use the VPORT registers, or load the address of the io port into a register and use an st instruction to write the data. If you decide to use a regular store instruction, it may change the timing of the loop so you may have to adjust the number of nops.