New JF Server Build

[KodiUser1138]

I've been planning to build a proper dedicated Jellyfin Server machine for awhile, considering different options for both the server and storage sides. I don't have a specific budget because everything is so fluid and I'm in CAD but I'm not opposed to used equipment. My build concept is for rack mounting and generally headless deployment (learning the fancy IT words). I am uncertain what hardware specs would be best, not Mad Max overkill but will handle my expected requirements with little issue. Once I have that sort of baseline I can determine budget and build. Here is what I am looking for suggestion/information about.

System:
Windows based as that is what I know and can implement easiest. When time permits I can look to other possible options.
Handling full 4K UHD Blu-ray rips, lossless spacial audio, with up to 4 active remote users requiring transcode and 4 local clients

Server:
3-4U rack case (on rails)
Intel based ATX MB (1+ M.2, dual/10Gbps Ethernet, USB 3 etc.)
Intel CPU?
64+ GB RAM?
Intel ARC GPU?
M.2 SSD for system
2.5" SSD for "extra" media (movie trailers, posters etc.)
2.5" SSD for transfer/cache/transcode
600W+ PSU
HBA PCI-E card
Assorted cabeling

Storage:
4U rack mount case (on rails)
3D Print vertical drive caddy trays for storage up to 46 3.5" HDD
Collection of HDDs
2 24-port SAS Expanders on PCI-E power risers
1000W+ PSU
FANS! (with controller)
Assorted cabeling

I have been designing the storage case for awhile, looking at various options. Basically trying to build a 45 Drives style case in a 25" deep case that is essentially just a JBOD disk shelf. No RAID required so drives work independently and can remain sleeping 99% of the time. Not here to debate that issue, it's my preference. Back-up is a near duplicate build off-site.

Welcome all suggestions and information. Want to build a good system, easy to work with and useable for a good decade all things working well. MY current JF sever is running on a multi-purpose 13 years old machine with NAS/clients for storage.