Using a RF433 transmitter on an Argon to emulate the remote control for window blinds - should I use PWM?

I’m trying to use a RF433 transmitter to control window blinds by emulating the remote. I had it working using an esp32 but can’t get it to work properly using an Argon. There seems to be a timing issue.

The transmitter is activated using a digital pin held up or down for periods which match the codes sent out by the remote. I developed the codes/timing using a SDR receiver. The signal pulses range from 250 us to 5 ms.

I have SYSTEM_THREAD(ENABLED) but the transmissions still seem to be interrupted for some reason.

Is this something I should be using PWM for rather than just holding the pin high or low using delays?