You can scavenge the end (high level) parts from any of the published modules and modify them for your party. But the primary thing to remember at those levels is that you should expect to always customize to your party. The mix of powers and magic makes it impossible to write a universally appropriate module for those levels. All the authors can do is give you a good foundation.
It's just that: the foundation isn't good. High level 5E material is written like low level 5E material: for neophytes.
Let's just say if your expectation for a "good foundation" is an adventure that might just challenge new players who grab high-level characters and go, then you're in luck.
If, on the other hand, you expect high-level play to be geared towards more experienced players (the way all players become if they've played their way through all the levels), and indeed games with options turned on, boy are you going to be disappointed.
Put another way, I'm dead tired of using "every group is different" to justify WotC's incredibly weak efforts at high level.
Yes, the DM can't expect a high-level scenario to be perfectly tuned to his or her group. No, that does not excuse the woeful state high-level 5E is in.
I'm not exaggerating when I say a well-tuned team of options-on characters can easily handle a high-level adventure when they're five levels short of the intended level range. What this means is that once you've levelled past 15th or so, the official support pretty much isn't there, like, at all. You're on your own - completely.
My point is that WotC's choice to cater to newbies and carebears at low level is understandable. Not upping their game at high level, where players naturally will have prior experience, is, on the other hand, completely inexcusable.
Tldr if your players are veterans, expect to have to make your own encounters from level 12 or 14 or so.