Well, it varies. I visited Czech Republic four months ago and wow I thought, for the people were quite cold there. Not rude or anything like that, but I was just a little bit surprised cause they seem very tired of people who were tourists (I’m Polish-Russian) and I tried speaking some Czech since it’s similar to Polish, but I guess my accent was off and that made them annoyed.
However the young people were very nice! Inviting and friendly, while the elders were cold and reserved. Maybe it’s a mannerism from the communist era? There are elders like that in Poland and Russia too.
I think we all Slavs are beautiful and amazing, we shouldn’t rat anyone out and categorize who’s the most Slavic. However there are countries who might embrace the slavic culture more, but it doesn’t make any countries less or ashamed of their heritage. Czech Republic might be more Germanic in its behaviors and mannerisms, maybe because they’re closer to the west and been a part of the Roman Empire as stated in the comments. But I dont think they’re less slavic because of that, maybe more reserved as the west, but always in our Slavic family.