Here's what I see on initialization. Initially, another addon AllTheMogs was in the call stack, after disabling AllTheMogs, ArchonTooltip shows up in the same spot. Assuming from this that LibStub is a shared dependency between several addons?

Message: Interface/AddOns/simpleitemlevel/addon.lua:28: Cannot find a library instance of "LibAppropriateItems-1.0".
Time: Sun Aug  3 12:30:51 2025
Count: 1
Stack:
[Interface/AddOns/ArchonTooltip/Libs/LibStub/LibStub.lua]:40: in function 'LibStub'
[Interface/AddOns/simpleitemlevel/addon.lua]:28: in main chunk

Locals:
self = <table> {
 minors = <table> {
 }
 minor = 2
 libs = <table> {
 }
}
major = "LibAppropriateItems-1.0"
silent = nil

Let me know if any other information is needed. Thank you.

Could you check whether [addondirectory]/SimpleItemLevel/lib/LibAppropriateItems-1.0 exists? Also, tell me which OS you're running this on?

Alternately, could you check out the new release? It includes a potential fix.

I found the problem (it's me lol). I was referred to this github project by a reddit post, and found no match in curseforge for "simpleitemlevel" -- I see now it's searchable as "simple item level". I had assumed I could just download the git zip and sideload manually, but this had the unknown side effect of circumventing the curseforge packager process that reads external dependencies out of .pkgmeta.... hence a missing lib/ and the error.

Sorry for the user-stupidity... I greatly appreicate the quick response. Looking forward to using your addon :)

No worries. Technically you could download it here, but you'd need to get the zips that are in the releases section rather than the top-level download of the plain repo.