I’m only running a single eGPU + USB Controller passthrough and while it took some tinkering to get it started it has been smooth sailing afterwards. The B650 series of motherboards has mostly had good IOMMU groupings so there’s a good chance your motherboard will allow you to play around with some KVM/QEMU/VFIO if you wanna try gpu passthrough to a virtual machine.

Regarding Case: Generic I would look into getting one with dust protection (bottom and front) and preferably sound proofing. Having the dust get stuck outside the computer makes cleaning so much simpler and having a quiet computer is lovely.
Personally I’m a fan of the Fractal Design Define 7 but I imagine you can get a case with the dust protection and sound proofing much cheaper than that if you take the time to look around and read some reviews, especially if you don’t need E-ATX or multiple 3.5’’ disk slots.

Info that could help others help you:
House or flat?
Renting or owning?
How large an area do you need to heat?
How many rooms?

Temperature and savings:
Where I live they say that a house with people living in it should be at least 16°C (~60°F) to handle the moisture we generate.
Humans should have at least 18°C (64°F), preferably 20°C (68°F).
That means that you could close doors and let unoccupied rooms have lower temperature than the rooms you use.
If you’re stuck with space heaters then you’ll save quite a lot that way.

Now let’s look at Office. Open an Excel spreadsheet with tables in any app other than excel. Tables are something that’s just a given in excel, takes 10 seconds to setup, and you get automatic sorting and filtering, with near-zero effort.

I mean you have the same functionality in LibreOffice Calc, the automatic sorting and filtering is called AutoFilter and the table style is chosen from AutoFormat Styles.

It’s a problem if a projects wiki doesn’t have complete information, but I’d say that’s true whether it’s about their mailing list or something else.
My text was a simple quote from GNUs mailing lists page, so they definitely have it documented.

I’m not a user of mailing lists, but I can see the use of having all correspondence neatly delivered to your inbox where it can be subjected to whatever mail client rules you want. Especially if you are active in dozens of lists.

In regards to irc I recommend setting up a bouncer:
https://wiki.znc.in/ZNC

In order to receive messages from a mailing list you must subscribe to it. Additionally, many lists either require that you be subscribed in order to send messages to the list, or that your message must be approved by a moderator if you are not subscribed. See listinfo for a catalog of the various mailing lists. Each list in the catalog has a link to a page where you can subscribe to it.
https://lists.gnu.org/

I imagine these could be good starters for you:
https://lists.gnu.org/mailman/listinfo/gnu-misc-discuss
https://lists.gnu.org/mailman/listinfo/gnu-system-discuss
https://lists.gnu.org/mailman/listinfo/social-discuss

memmy
https://apps.apple.com/us/app/memmy-for-lemmy/id6450204299
Memmy is built for the community, not for a profit:
Fully open source and transparent; all code is available on GitHub.
Completely funded by our community through donations.
No advertising, no trackers - ever.

If choosing Synology look into the Plus series (f.e. DS723+) or you end up with ARM CPUs and lose many of Synologys software goodies.
Their Active Backup for Business software is a nice way to backup the household machines as an example.
As you enter packages in this list you will see which models are supported:
https://www.synology.com/en-us/dsm/packages