This kind of issue is the subject of fairly regular discussion so it would be an idea to do a search of this forum, if you haven't already done so.
chat sniper wrote: ↑Mon Feb 27, 2023 2:19 am
First thing I noticed was that if I have a custom model set for a bot, the game will crash saying it cannot find the textures necessary for it. Once the relevant texture file has been put back in the default texture folder however, the game laoded successfully...
That's a bit odd, as normally the game would just load the model without textures and, failing that, load a default model. I don't recall ever having a crash because a model's skin could not be found.
The reason for most of your issues is that you don't have the .int files (and .ini files where relevant) for your mods/mutators/etc in your UT/System folder. Your issues indicate that the Engine won't look beyond the System folder for content that it expects to be in the System folder.
The custom bot model will load because that is called from your User.ini which, presumably, is in your UT/System folder.
The tournament Darkmatch is one of the gametypes in the Botpack.int file which, again presumably, is in your UT/System folder.
You don't need separate folders for .u, .ini and .int files (you could try putting all your inis and ints in your Expansion/System folder and see what happens).
chat sniper wrote: ↑Mon Feb 27, 2023 2:19 am
I'd really like to separate base content from custom stuff, so any help would be great. Thanks
There are ways to do that - it not something I do (beyond having separate map folders for the various gametypes and having separate system folder for different UT versions) so I can't offer any direct, useful advice. As I say, there are some recent discussions on that in fairly recent threads, I can't remember which ones but, hopefully, some digging around in this forum should be fruitful for you.
A thought - put ALL your int and ini files in your System folder, remove the /Expansion/Sytem int and ini folders and move your /Expansion/Sytem folder to be above /Expansion/Maps/*.unr (that is at the top of the Expansion folders). Try that and see what happens.