I've tried training at several places and noticed the difference is really huge - at fitness clubs, trainers often just don't know how to teach proper striking technique and stick to general fitness conditioning. Specialized muay thai gyms are better, but not all of them are near the metro, which is a downside.
I'd suggest searching through the 2GIS app and looking specifically at reviews from people who've been training for a while - they'll tell you about the quality of instruction, not just talk about how nice the gym looks. Pay attention to whether the club has different level groups and whether the trainers are willing to work with beginners (this matters because bad technique at the start creates problems later). You can always call and ask for a trial session - that's pretty standard everywhere.