Can you give a concrete example? Because I don’t understand what you mean.
Immich is absolutely not perfect yet for every use case. A lot of people are looking for a photo server that can be used together with an existing Digikam archive and while Immich has recently added a read-only mode it still does not have good support for hierarchical tags which is necessary for that use case. I hope they will add that feature soon.
That fan is not very standard though because it is a low profile 90mm. I only found a single replacement option thanks to a reddit post about this machine: Thermalright TL-9015W.