Questions about my server, my needs, and possibly a paid sysadmin

Serverman

Hello LET.

I own a machine, that i use for my personal stuff, but im running it on Windows server 2019. It works fine, but not perfect as i want it to. I want to convert to Linux, preferably Ubuntu, and i have questions!

First lets do the specs :

-Amd Rysen 3600x cpu, soon to be aa 3950x
-16gb ddr4 memory, soon to be 64gb
-500gb m.2 ssd
-Hosted on a 500/500 connection (private connection, not a datacenter)

System is running on ASUS ROG Strix B450-F GAMING, Socket-AM4 motherboard.
And yes, i know this is consumer hardware. No need to tell me that!

The server also has a 5 x 5TB USB hdd enclosure connected to it, with raid-5 on the box (no software raid within the OS)

The server is today used for :

-A decent size plex library, streaming to no more than 2 clients at a time
-Torrenting
-Hosting a few webpages
-A Rust game server (may shut this down)
-Local network storage

I want to go over to linux due to :

-Stability
-Speed up my webpages (iis is a pain in the starhole)
-Learn
-More possibilities for usecases

What is important to me if i go Linux :

-The USB storage can be unplugged and plugged into a windows machine later, so file system most support both
-A simple way to backup the entire ssd with all configs, files, os and everything. Also simple to roll it back
-Able to run both terminal and GUI, to more easily manage torrents in a torrent client, and file managing on the USB storage.

This is conserns i have :

-Running all what i want in the same OS might fuck up configs, crash things and so on
-Endless hours searching online to find solutions when issues appears
-Driver support for my motherboard (not even windows 10 takes my ethernet drivers, have to be manually provided)

So, here is a few questions :

-Is there any tools out there, who can make a image of my entire SSD on the server with preferably 1 command? And if yes, how can i easily roll it out to a fresh installed system, if i mess it up (who i will do at some point)
-What file system to i need on my USB storage to be able to hot plug it between linux and windows ? The box is mainly used for plex library and backups
-What distro should i go for ? Because i want a GUI due to easier torrenting and file management, i guess Ubuntu. But how about Debian?
-If i was to pay someone to help me set the box up, what will that cost me? The person must also be able to provide some sort of support, and help me later on (for payments) if i need it.

Thank you for your feedback. I have SOME, but not alot of experience in Linux. I do for example run a few vms with virtualmin / webmin installed, but that is basicly 2 commands to install, and it just works, all the time.

Have a nice day!