Recommendation for rental property sites

Hi everyone, I will be moving to Bangkok for work next month and I am currently looking at my options for places to stay. Originally I wanted to do 3 months in some sort of serviced apartment until commiting to a 12 month contract, but I'm not really happy with the options I can find for that amount of time using websites such as Airbnb, booking.com, Agoda, etc.

Now I am considering to do a couple of weeks in a hotel, spend that time looking at some long term rentals and then commiting earlier than planned. For this I'm using Thailand-property.com and ddproperty.com, but I am wondering if there are any further websites/apps commonly used in Bangkok.

Thank you in advance for any advice!