It has basically all the drawbacks a VPN has (most sites will distrust you on recaptcha, speed bumps, sometimes a connection gets timed out or dropped) whilst having a shitton of latency on top of that because y'know, it's free. There's always been more people willing to use TOR than the server space needed to prevent overburdening the network (in no small part because running the server space needed usually incurs significant legal risks since congrats, you've now become a target for law enforcement to bust your door down and ask why an IP you own a machine on is being used to upload CP to the clearnet - few people want to deal with this scenario for blatantly obvious reasons).
This isn't really something you can fix, it's just kind of an inherent issue with the protocol.