What all of you seem to forget is that the instructions to compile a23 are quite different from the instructions to compile recent versions of 0ad and that the versions of some libraries a23 depends on aren't available on modern Linux distributions. In my opinion that makes compiling a23 on a modern Linux distribution quite complicated.

@NewWorldBohate You're exaggerating when you say compilation is difficult. The description on the website: https://gitea.wildfiregames.com/0ad/0ad/wiki/BuildInstructions#linux may be confusing, but that's because it describes compilation cases for various distributions. If you write down the commands, for example, on a piece of paper, it's not so bad. I can help you with that—you just have to want it and show some good will. Yes, compilation requires a lot of dependencies, which are normally unnecessary. But compilation can be performed on a Live system running from a DVD or USB drive (it must be the same version as the one you have installed on your PC). After completing the necessary steps, back up the necessary directories and shut down the computer. All the "mess" (as you wrote) is gone – you only have what you need. Transfer it to your PC and you're done. A small note about 0ad. You build the Live installation in a directory on an external drive, as this directory takes up a lot of space. The drive must have Linux partitions (ext4). If you connect a USB drive with a FAT32 or exFAT file system, for example, the build will fail because Windows file systems do not support symlinks. Best regards.

Editing directly in the XML files? Not very simple for most people. There are at least 8 python scripts in the pages you linked. 

what about updating your maps and scenarios to the current or next release? https://gitea.wildfiregames.com/0ad/0ad/wiki/PortA25ToA26 https://gitea.wildfiregames.com/0ad/0ad/wiki/PortA26ToA27 https://gitea.wildfiregames.com/0ad/0ad/wiki/PortA27ToR28

As feared this is turning into a nightmare fast. Ive tried a wine/proton version before. This is a big difference when playing a windows version thru wine/Crossover etc vs a installed version in Linux. Appimage also. Not good.   I have dozens of customized scenarios/skirmishes.    Again the compile option(s) ARE too hard and a mess to do. The build instructions in the link start by focusing on all the packages and additional  software you need to even consider compiling in Linux, and its ridiculous as the Windows versions are completed in the basic .exe install packages where anything Linux are raw and have to go thru the compile nightmare. Obviously previous Linux (Mint) versions of 0AD pumped into all the Linux Mint repositories were completed in a .deb format, and now are no where to be found.     Just for FYI- my current install is in the outdated Mint 20.3. Ive even taken a good image of the entire install, placed on a new SSD on the new PC build, and it, of course will not work as the drivers built in the 20.3 kernels are outdated and do not work with new CPU and chipsets..  Doesnt matter if you 'forcibly' and manually install and try any of the new kernels in 20.3, same result.