Although muOS sorts items alphabetically in Content Explorer there is a trick you can do to force a specific order.
For changing order of folders, this option Configuration -> Interface Options -> Friendly Folder Names needs to be enabled
Edit MUOS/info/name/folder.json so that the display name is prefixed with something like [001]
"msx2": "MSX2 Computer",
"n64": "[001]Nintendo - 64",
"naomi": "SEGA Naomi",
"nds": "[002]Nintendo - DS",
"neogeo": "SNK Neo Geo",
Which will make content explorer look something like this:
You can then you can go into Configuration -> Interface Options and set Content Name Scheme to Remove [] which will result in:
Sorting Game Names
The same trick can work for game names but instead you edit MUOS/info/name/content.json. For example in order for Mortal Kombat Trilogy to display in release order you would do the following:
"mk": "Mortal Kombat[1]",
"mk2": "Mortal Kombat[2] II",
"mk3": "Mortal Kombat[3] 3",
Sorting Games in Collections
If you go into MUOS/info/collection/{collection name}/ you will see a bunch of .cfg files. The 3rd line represents how the name is displayed on the collections screen. Add a prefix to this name like [001] to control the sort order. Like above if you don’t want to see the [001] you can go into Configuration -> Interface Options and set Content Name Scheme to Remove [] specifically.