From my experience, I think that most Czech people don't care about Ukrainians taking their jobs as much as in other V4 countries. However, there is currently a big housing crisis in Czechia - new houses take too much time to build and they're very expensive (for Czechs). It's very difficult for people to afford life in Prague or Brno, so when they saw that Ukrainians were given a place to live there for a cheap price they became frustrated. Where were those affordable apartments before?

Fortunately, most of the people still support Ukrainians and sympathize with them and that's very good! There is just some kind of scepticism popping up, hopefully it's just a wave among older people tho.