We have the same rules in Czech Republic, company usually won't let you leave before your notice period, definitely not corporate.

Acquiring new job usually means giving a notice and begin with search during notice period. Some companies will wait for you for 3 months but terms are usually not good.

But it is also a benefit because so many people have a long notice period so when you start searching after you give a notice your competition is tighter.

But it is still kinda a risk.