Where did you spend the 1- 1.5k on? Since accommodation and travel was basically free

If you want to pay taxes in Bulgaria, they will take it regardless if you spent 183 days there. Bulgaria is not going to be a problem. The problem is The Netherlands, if they do a check and decide that you have no real home base, based on your nationality they can still tax you.

I’m in the same situation, but I decided to move to Bulgaria last year.