TL;DR:
The distro you use DOES make a difference with the software you want to use it with. Yes, they pretty much have access to the same software, but how that software runs out of the box can be very different based on the distro it’s running in.
The Background
I’ve been using MX Linux on weekends to get myself used to it, as I will eventually buy another laptop for Arch and convert this one to MX Linux only.
Recently, I decided to try out gaming on MX Linux using the official MX/Debian repo for Steam. Prior to this, I had actually started replaying Tomb Raider 2013 on Arch(craft), and like I said in another post, it’s the first time in a while since I was able to turn the graphics settings all the way up without seeing any significant performance penalty. In fact, the penalty for doing so on Arch is so minimal that I would actually need to benchmark it to be sure, as it’s hard to see it otherwise.
Anyway, so I installed Steam on MX and downloaded Tomb Raider, and set it to Proton 9.0.4 just like I have it in Arch(craft). Confident that there would be no difference, I turned the graphics all the way up in the launcher because it’s the same device, same proton, same Steam(?), so everything is no doubt gonna be one-to-one.
I could not have been more wrong. 
At the game’s main menu, I was met with FPS so low, I really thought the game was about to crash. I immediately headed to the graphics settings and turned them down to normal, waited several seconds for it to calm down, then exited the menu to resume my save.
And what guess what? That didn’t make the difference I was hoping for. The thing was still quite stuttery! WTH?!
I know the Nvidia 555 drivers are not as good as the 580/590 ones, but it shouldn’t make playing the same game on the same hardware be so much different. There is something not quite right with the way MX Linux/Debian goes about drivers causing this, or maybe it’s just my setup specifically.
However, this doesn’t mean it’s all sunshine and rainbows in Arch. For instance, using KDE 6.3x in MX Linux is so smooth, it makes you actually enjoy the desktop a little more. In contrast, using KDE 6.5x in Arch is noticeably slower. Sure, this could be in part due to my hardware, but I have no doubt it’s also software, meaning the distro, as well.
Additional Note:
This also affects hardware/firmware. Audio on MX Linux needs to be tweaked to work correctly without crackling (for my device), even for regular music and videos. In contrast, on Arch(craft) and Ubuntu Studio, whether it is just streaming or low latency audio production, things are ready to go out of the box.
This would confirm that specialist distros and bleeding-edge distros have several advantages in multimedia, gaming, and so on, specifically out of the box. Again, duh! 
As Final Note
I went through the process of trying to get the Nvidia 580 drivers by using ddm-mx, MX Linux’s driver manager, but it only provided the 535-550 and 590 drivers as alternatives for my hardware.
The latest driver (590) is not compatible with my Nvidia card (Pascal), but I tried it anyway. It installed, the system loaded it, but it didn’t really load it, it just registered it as the driver. I tried Tomb Raider again and there was no difference.
Ultimately, I decided to go back to the default MX Linux provided driver, which I have apparently failed to do properly since my system somehow still thinks I have the 590 driver in certain areas, but shows the 555 driver in others. In any case, this Frankenstein system has actually made it so that Tomb Raider now runs perfectly on MX Linux at max graphics, just like in Arch(craft). 
I dunno how, but I will not touch drivers again unless I actually run into an issue. 