Openly? Hardly. You are to know a place and how to ask for it.

While true, it's trivial to find this info on Google Maps.

I've only found some shops claiming they only sell CBD products and not THC. Perhaps I'm doing it wrong, I have little experience with Google Maps, I've just opened Google Maps and searched for weed and cannabis.

Weed (THC) is illegal in the Czech Republic, thus it is not openly advertised. Search for a "weed bar prague" in ordinary google search; various forums and reviews will show up. Then put some bar name into google maps and there will probably be a "user guide" in reviews. If not, then move to the next one - there are dozens, if not hundreds. If there is no guide and you're certain the bar sells weed, simply ask for it directly, usually the only requirement is to buy a drink first.

>usually the only requirement is to buy a drink first.

And if you obviously have no clue what you're doing and don't even try to buy a drink, they'll definitely know you aren't a cop and offer you the weed.