It's made impossible to leave Nimbus Note once invested

It's made impossible to leave Nimbus Note once invested

I wanted to try Notion and move my notes up there. Unfortunately, there is no way to do that. The html export creates notes that have no title once reimported into Notion and all the pictures are missing. I created thousands of notes in about 1,5 years and its not feasible for me to reinsert all pictures.
So basically I'm stuck using Nimbus Note until... when exactly ? Forever ? There has to be an export feature that makes it possible to switch to another note taking app, otherwise using Nimbus Note, once invested, just holds my notes hostage. That cannot be intended and would be highly malicious by NN.

Please make it possible to export my notes in a way that other note taking apps can make use of it or alter the html export feature accordingly.