That's unfortunate, it really does run well on Steam Deck. I'm dealing with my own NVIDIA issues trying to get hardware acceleration and it's not been fun at all.
I cannot say that I love Linux, in fact it annoys me daily lol. I want things to just work and itends up wasting tons of my time to get only part of the functionality I was hoping for. The Steam Deck has been great, though my media server at times has made me wish I never wanted to self-host in the first place lol. (been kicking around various attempts at varying levels of success since 2017). From here, tl;Dr I am very stupid, I'm well aware, but also why is Linux so complicated? It seems counterproductive to need to be so heavily invested in something when it's goal is to keep you more hands off so you can focus on other tasks?
I feel like a broken record but I really want some medium between having full control over my OS and things just working. It doesn't help that there's OS specific syntax making anything outside of official documentation a hail mary. I've no love for Windows either but I've only been limited by it a couple times and I just wish I could say the same for Linux.
Of course, the limitations I've reached through Linux are entirely my own incapabilities, but that's kind of my issue? It seems redundant to have to know the entire ins and outs of it when the point of getting these tools to exist was to mitigate our tasks? I make music, art, I wrote and have a bunch of tech hobbies. I've spent time learning, but goddamn I just don't have the time and as time from the server hobby passes and I'm basically starting fresh. I just want some inbetween from needing to know the entirety of my OS and being locked out of it. It just seems that this hobby more than others, at least for me, needs to have the most consistency while having the least consistent sources of information due to immense level of knowledge that there is as well as the fragmented nature of each distribution.
On another note, I find it amazing how much easier Docker and its tools are in Linux than it is for Windows. Now that's funny! And it seems poignant to your issue as well... Some software is made for certain things, and translating that can throw a wrench in things. Docker on Windows, like NVIDIA on Linux, just weren't made with each other fully in mind and as a result have been made to retroactively "work".
Which is really too bad. It's pretty unlikely that something like Rocksmith2014 will ever work smoothly out of the box in Linux - it can be made to work with lots of work but... You can also just dual boot windows. Unless you're extremely familiar with the OS, chances seem high that the entire process of downloading and installing Windows then downloading and installing RS2014 will take less than 1/3rd of the time.