It's no surprising you got no replies to your question.
This is mostly a fan site and your question is very specific, as it's really hard to tell which of the tennis clubs/academies is the best and what the main differences between them are unless one has hands-on experience with each of them.
All of the above three look fine, just pick one and you'll see.
You can also check (google translate) the link below, which lists some of the top academies.
Tenisová mapa České republiky: V jakých klubech rostou ti nejlepší tenisti? | Tenisový svět (tenisovysvet.cz)
If I were you I'd maybe look at LTC Pardubice, which is praised in the above article. It's a lovely half-historic/half-industrial city just one hour by train from Prague right in the middle of Czechia (i.e. cheaper accommodation) and since 1926 it hosts one of the best junior events in the world. Just check the past winners of the event and you'll be blown away (like I was):
Pardubická juniorka – Wikipedie (wikipedia.org)
And below is a full list of all tennis clubs in the Czech Republic (just enter the region desired):
Český tenisový svaz - Adresář klubů (cztenis.cz)
For instance, if you choose Praha (Prague), a list pops up and you'll see that the Czech capital has 198 clubs in total.
Good luck!