Running lower-level games with higher level characters

My group just finished Storm Kings Thunder and are at level 12.  We're looking for our next adventure and considering the two Waterdeep games.  Would it be a mistake to start with Dragon Heist since it nominally starts at level 1?  More generally, are there good ways to play intro-level games with higher-level players?

Most of the larger official modules can be started at level 1 or somewhere around 3-5 (a lot of them have intro sections that can be skipped or glossed over). Very few official adventures start that high, though. You could look into addons from Tales from the Yawning Portal, some of those are geared for higher levels. You can also try a level-filtered search on the Marketplace , although it doesn't seem to do a great job of catching the level (I see a lot of low-level returns).

You can find a lot of balancing 'patches' for official content online! No D&D adventure can't be buffed, no adventure safe for your players no matter how high their level!