It depends on where your land is located. If it is in the south or central part of Thailand, I would plant durian trees. However, they are not easy to manage.
I have spent 9 years and approximately 30,000 baht per rai annually on maintenance. Each tree can produce up to 80-110 durian fruits per year. The market rate for each fruit is 100 baht per kilogram, meaning that each tree can generate up to 36,000 baht. Under Thai law, you can plant up to 25 trees per rai, so each tree should earn you 6,000 baht per year.
If you have 10 rai of land, you could earn (25 trees x 10 rai) * 6,000 baht = 1,500,000 baht annually.
However, durian trees are very difficult to maintain. There is a chance that they will die. It takes 7-10 years for them to produce fruit.
*My wife owns 20 rai of farmland in the south. The durian trees are already planted there, so I did not have to wait for them to produce fruit. However, it may take some time for your investment to pay off. In my opinion, the price of durians will only go up. It is very unlikely that they will go down.
Teak trees would not be profitable because you can buy teak wood at a much cheaper rate like 1/10 cost in Myanmar & Laos.