If you asked more specifically about the Czechs’ “most favorite foreign nations”, there have been lots of surveys, such as this CVVM survey in 2017:
Slovakia won (and almost universally wins, they’re our brothers so it’s just a proxy to loving ourselves – and Czechia wins if it is allowed to compete) ahead of Austria (which is always at the medal spots) and France. I think that most other surveys place countries like Denmark and Switzerland higher than France. Many other medium-sized Central and Western European countries end up near the top. For some time, Germany is no longer near the very top, for numerous reasons starting with their asylum policies.
So Germany ends up in the better half, like the U.S. and e.g. Poland – which we unfortunately love less than Poles love us. Russia along with Ukraine, Israel etc. are in the lower part of the middle, despite our being one of the greatest allies of Israel. And after places like India, China, Latin America etc., the bottom is generally occupied by Islamic nations, with countries like Afghanistan, Pakistan, Palestine, Iraq, Syria near the rock bottom. (Well, for our being great allies of Israel, it’s probably enough that we love Israel much more than we love Palestine which is perhaps unusual in Europe! Just to be sure, the answers are surely non-uniform, Israel’s mediocre score is an average of some great Czech Israel fans and Czech anti-Semites, among others.)
This criterion isn’t quite the same as “admiration”. We don’t quite “admire” Slovaks. But that’s one problem. If someone is worthy admiration, many Czechs tend to be jealous. So I think that Czechs prefer and like nations that they don’t have to admire too much. 😉
If you could get results about pure admiration with jealousy removed, I think that some usual successful countries would win, the U.S., Germany, Switzerland, Sweden, Norway, Japan etc.