The main reason is Crew entry requirement in TPE and HKG; Both would require Quarantine which is not possible for crews to be blocked 2 weeks. That is why they do a stop in BKK to change crew ( on top of disboarding some passengers, I doubt they have local traffic right on BKK-TPE or BKK-HKG sectors); The crew will do BKK-TPE- BKK or BKK-HKG-BKK without entering either HKG or TPE. They will then rest in BKK and then fly for another local Asia rotation (HKH or TPE) or fly back to AMS.

So for one Crew typical routing would be :
Day 1 : AMS- BKK
Day 2 ; arrive BKK
Day 3 : rest in BKK
Day 4 :depart for TPE and return BKK
Day 5 : Rest BKK
Day 6 BKK- AMS
Day 7 : end of routing;

Same thing was happening earlier in the Pandemic with flight to China with a crew change is Seoul;