you should have applied in Australia. online evisa, only took me 7 working days to get approved.

why don't you apply online?

also prepare a letter to confirm that you are eligible to work remotely.

if you haven't leaving your country yet, I suggest you apply at your home country embassy.

DTV is valid for 5 years with multiple entry. So you don't need to renewal or extend every year. However, each saty is 180 days. If you are planning to stay more then 180 days, you need to extend your stay at immigration office for another 180 days. Even though, you can stay 180 days, you still need to submit TM90 (Notification of staying in the Kingdom over 90 days), before your 90 days stay due.