[wrxtasy]

...Whether they wil do all the other stuff you want is a different matter. Can't comment on that as I don't source my content that way. However I run a separate media server based on an unRAID x86 box that handles all my file storage requirements, and can also run applications to do what you wish I think. I think achieving silent handling of this element of your requirements could be more of a challenge - but I house my server in a separate room (actually a large storage cupboard) so it doesn't have to be truly silent...

And just to complicate matters there is ARM and ARM64(aarch64). There are numerous 32bit programs that have simply not been brought up to speed to run on ARM64 OS's. You need to be very careful expecting that all ARM64 Linux boxes can run everything.
Widespread Docker support is a classic example thats spring to mind for ARM64.

I believed the ARM64 RPi3 is still running a 32bit OS.

...CP, Sickbeard/Sobar and Newsreader together, fully automated...

Leave all that for a x86 server device.

There are enough cheap, small, silent HDMI 2.0 AML S905 devices getting about at the moment running decent versions of LibreELEC, that they have virtually become throwaway items. And yes they now very nearly decode everything a regular Kodi user would play, even FLAC and AAC with recent Multichannel PCM Audio improvements.

So, Don't try and do everything on the one device unless you are willing to pay big $$$ and be an early Tech adopter.

[noggin]

...Whether they wil do all the other stuff you want is a different matter. Can't comment on that as I don't source my content that way. However I run a separate media server based on an unRAID x86 box that handles all my file storage requirements, and can also run applications to do what you wish I think. I think achieving silent handling of this element of your requirements could be more of a challenge - but I house my server in a separate room (actually a large storage cupboard) so it doesn't have to be truly silent...

And just to complicate matters there is ARM and ARM64(aarch64). There are numerous 32bit programs that have simply not been brought up to speed to run on ARM64 OS's. You need to be very careful expecting that all ARM64 Linux boxes can run everything.
Widespread Docker support is a classic example thats spring to mind for ARM64.

I believed the ARM64 RPi3 is still running a 32bit OS.

Yes - Pi is still running a 32 bit OS (partially to enable all Pis to run the same distro image) but also because of some other issues.

However the workload required for the OP's other requests are much more CPU and disk IO heavy than media playback on a device designed with hardware video acceleration. That CPU level is far better accommodated on an x86 box IMO. If you are running lots of file manipulation stuff (decompressing, checking integrity) I'd do that on an x86 box with SATA connected storage - it will be faster, and remove a potential bottleneck. With unRAID you can run docker images on the OS to handle lots of this stuff - as well as run things like TV Headend etc.

I totally agree about separating media storage and manipulation from playback. With media player hardware constantly changing and improving (and being incredibly low cost), it's better almost to treat your Kodi box as a cheap appliance for playback duties only, and offload media storage (and sourcing) to a more stable backend optimised for it.

[nickr]

I think the OP should perhaps try replacing his fan (not just cleaning it) and he will have a machine that will make a great server, with a bit of external hard drive space added perhaps.

Then buy a C2 or wetek for playback of h265 etc and he'll have a great experience moving forward.