Traffic correlation: All the large state actors are well capable of recording every single IP transaction between devices. You can create detailed correlation maps from these transactions. Considering that this wouldn't cost much for state actors to implement, one has to assume such traffic correlation systems currently exists.
Node compromise: It costs less than 5 dollars a month to create a TOR node. There are currently ~8000 TOR nodes/relays in existence. That is 40k USD per month (at most). Do you really believe state actors can't afford 40k USD per month to compromise the vast majority of TOR nodes? Even a single millionaire can compromise the vast majority of TOR nodes.
Another problem is that TOR is an outdated privacy tech. considering modern state actor capabilities. Mixer networks + network jitter is necessary to protect privacy at this stage, yet no such project exists yet.
TOR is not a good option for privacy. Currently only valid option for privacy is external Wi-Fi jacking and ensuring you don't send any private info like CPUID.
Or alternatively, you can hack routers/computers and put your own TOR nodes in them, then you can only use these known nodes.