TT is known as a world-class coach with a great CV including a CL win, but his current performance at Bayern is food for thought.
It's also known that his former assistant and video analyst Benjamin Weber left him upon the Chelsea sacking. Weber was reported to do more than what his job description entailed, as in stuff like communication, especially in Chelsea. TT lost him after his last sacking, and it's no coincidence that he's now exposed for the clueless moron he is instead of the dashing genius he managed to present himself as until now. Weber doesn't work for him anymore, having left for the sporting director job at Paderborn.
Since Weber's departure, TT's tactics have been pretty subpar for Bayern. Except for the BVB (copying Julian Nagelsmann's tactics, but there was probably massive pressure from the players as well as the media to bring Nagelsmann's football back at the time), Köln (good call on Baumgart playing offensively given TT's long ball tactics without expending too much energy after the international break), Stuttgart (underdog ball against a naive, overconfident VFB), and Wolfsburg (decent football and good adjustments in the second half) the games were either average at best or the opponent was imploding anyway.
In addition, he and his tactics were usually praised by his players in Mainz, Dortmund, PSG and Chelsea despite them having been through brilliant coaches like Jürgen Klopp, Carlo Ancelotti, Unai Emery, Antonio Conte and Maurizio Sarri. You can argue about his offensive prowess, but even that didn't stop him from being largely successful back then, or the players from respecting him and approving of his tactics and methods. However, it's far from the case at Bayern. The players were devastated that Nagelsmann was sacked last season, and didn't seem to respect TT much, seeing him as lacking. Even Kerry Hau, who is considered a good, reliable journalist, reported that the players had complained about his lack of communication and inability to develop the playing style further not long ago. If the coaching and training were adequate but the players couldn't execute them on the pitch, they wouldn't criticize the manager.
You could argue that Bayern is a big club with huge egos and toxicity, but it doesn't explain him succeeding at PSG anyway despite them being by far the MOST toxic club in the world. There doesn't seem to be an Ancelotti situation where he doesn't reach the players. It's his own culture and country. He even managed to deal with the egos at PSG, so there's no dress room excuse. He has the charisma to handle big clubs and big players, leaving only simple incompetence as the culprit.
There's another reason that might explain his past successes: there were also plenty of highly intelligent field generals in his past clubs whose on-pitch coaching and leadership he took credit for: Hummels and Gündogan at BVB; Neymar (dismissed as just a stupid diva but in reality is highly underrated tactically), Verratti, Thiago Silva at PSG; Thiago Silva again, Jorginho, Kanté, Azpilicueta at Chelsea. He's nowhere near the tactical nerds that Klopp, Pep, Emery etc. are, so he needs a bunch of field generals to do his job for him on the pitch unlike these geniuses, who can micromanage and train anyone to play the way they want.
His current Bayern failures can only explained by TT losing his tactical edge for some inexplicable reason, or never having had any in the first place and just relying on others to secretly do his job for him in the past - Weber and his field generals, making him an utter moron and a lazy fraud who coasts on others' intelligence and hard work. Unfortunately, society allows such people to flourish. Soft skills and ability to market yourself are valued far more than honesty, principles and actual competence.