Yeah, saying “I left because I didn’t like it” makes prospective employers wonder what will stop you from leaving your new position when its downsides reach you. It sounds like you’ll just bounce around until you find the job you hate the least.
If it’s framed as “I want to leave because this job has things that I want”, then there’s no reason to believe that something new will push you out.
… though I do find myself wondering why OP believes it’s unrealistic to value a well-maintained database… especially in Germany, given the stereotypes! Lol