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     Just for FYI- my current install is in the outdated Mint 20.3.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placed on a new SSD on the new PC build, and it, of course will not work as the drivers built in the 20.3 kernels are outdated and do not work with new CPU and chipsets..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.        

Reconstruction of the Villa of the Lions in Ostia Antica, 3rd century BC, Italy. Illustration by Giorgio Albertini. Etruscan temple of Tarquinia called Ara della Regina (queen's altar). Built in the 4th century BC.