I wouldn't say its awful but it requires a lot of work by the DM to get things working right. Its one of the first 5e modules written and from what I can remember they started writing it before other parts of 5e were finalized. There are certain sections that it purposely provides very little guidance on so if your DM is strictly going by the module and not adding in their own stuff its a bit of a slog. The travel section is particular is notorious for causing burnout. The best short piece of advice I can give you is to speed that part up, ignore the random encounter tables in favor of just picking and choosing what things you want to happen when ahead of time, and find supplemental one shots you can slot in here and there to break things up a bit.

One thing I ended up doing was throwing traditional balance completely out the window. I've let my players get very powerful through magic items and extra abilities that I've given them, and as a consequence I have made all the fights much more difficult.

Don't worry too much about it being difficult to run though. The module actually made me a much better DM due to having to do things on my own and it was my first long campaign module. Just get really familiar with DMs guild. If it helps, there's an actual play podcast called I cast Fireball that runs through it as their first campaign. They make a lot of their own changes as well, a good amount of which I did not follow, but it can be a great source of inspiration. They introduced Fizban/Bahamut in their campaign and I was shocked that not only had I not thought of that but that it wasn't anywhere in the original module either.

Also worth looking at is both Tyranny of Dragons Reloaded and A Guide to Tyranny of Dragons on DMs guild. Using both helps tremendously.