Imo go straight to archlinux. With Archinstall it is significantly less work than people say, I got mine working in less than an hour, with minimal issues. I was on Manjaro for a while and loved the experience, shame about the issues they have. EndeavourOS seems alright but i had issues with the live image (no wifi)

I think an important consideration is which desktop environment you want to use as you're more likely to get better graphics support with a distro that defaults to your favourite de.

I used to use Mint, but I recently switched to OpenSuSE as I have decided I prefer using KDE. I could install KDE in Mint but I had a few graphical glitches and annoyances with it's apps being designed for cinnamon/gtk. Meanwhile no issues with OpenSuSE. I also have an Nvidia card and AMD CPU.

The other thing to consider given your graphics needs is a more gaming focused distro. I use Nobara on my living room PC which I use for gaming; it's pretty good although that machine is an AMD iGPU. I have considered moving that to OpenSuSE for consistency with my desktop but I like it as it is tbh.

I tried Mamjaro in the recent past - it's nice but I didn't like the Arch packaging system. The AUR is good but I've found everything I want via other routes on other systems, and Mamjaro failed on me soon after I started using it. May have been coincidence buf I decided I couldn't use a system like that - I just didn't want to be problem solving so much on my daily driver.

I've also tried Fedora. I really didn't like that system - again it was the package management system and the BTRFS file system caused me endless issues.

I like OpenSuSE's Yast and Zypper package management tools. I also like the debian Apt package management system.

Last consideration: Debian systems have a lot of support available due to it being the base to lots of derivatives like Ubuntu and it's own derivatives like Mint etc. OpenSuSE has less of that generic support - it's there but it's not the same scale, ubiquitous support.

I dont get the "alt" do you want CentOS (which doesnt exist, but I think Stream is better anyways) or Fedora?

Run Davinci resolve in a container, no internet access maybe, fixed dependencies that dont update. Ublue has a container image that you can run with podman.

Choose the OS you want and then use Distrobox to create a CentOS or Fedora environment for Resolve. It will see all the packages it likes.

Absolutely do not use Manjaro.

My favourite on your list is EndeavourOS. You can use pacseek to manage your packages if you really hate pacman ( though you should be use yay on EOS anyway ). If your really want a GUI, use yay to install pamac ( yay -S pamac or yay -S pamac-gtk probably — I cannot remember the package name and I am on my phone ).

If you like Debian, use Debian. The packages in Debian 12 are not old yet. Regardless, the package problem is solved by Distrobox.

I have debated using Debian as a base with access to Arch packages via distrobox myself. I may try VanillaOS for that. You would need to pick a different package source if you do not like the pacman commands.

What DE do you order? An alternative to Debian would be LMDE. That gives you the Debian stability and compatibility with some of the friendliness of Linux Mint and a more up-to-date desktop.

Use the AppImage for FreeCAD, it will probably have the best performance. You can try Flatpak if you want and compare but definitely not the snap.

Davinci Resolve will depend on the graphics drivers. If you have Nvidia you should be good to go, just pick a distro that has excellent integration with Nvidia drivers with zero fuss and tinkering.

Godot is Linux native software so I imagine it will work great on any distro, but keep in mind having recent enough packages for it.