The EU is built on rules that uphold liberal democratic principles, agreed to by national governments in a flush of post-WW2 clarity, and which tie successors to the same principles. There are exit mechanisms, but they impose large costs (i.e. Brexit).
You're saying nothing concrete in particular.
What rules? How do they inhibit change?
The only thing I can think of which is actually difficult to change is the echr and i see more than a dozen mostly liberal governments queueing up to change it (to little effect so far) over migration issues.
There are rules about election conduct and free operation of courts, to give two examples. Both of which Hungary skirts on occasion but the EU does apply some pressure.
