While not a direct answer to your question, you might want to consider M-Disc as a viable long term storage alternative. Much cheaper than tape and guaranteed to last at least 5 years (safe realistically for at least 10 years)

Always flying. Parking and starting increase wear and tear over time.

Check r/homelabsales. Especially for Black Friday, you get some fantastic deals. For like 200-300, you might get an r730 or r630, which would be way better.

Minecraft is fairly safe. Just open the port through your router and point to a dynamic DNS (if your friend just doesn't want to use your external IP)

Just install truenas scale on bare metal. Then side install proxmox on it (since scale is just Debian). You can have zfs having direct access to the disks and have VMs, LXC or Containers running on it.

Honestly, you do you. Stick to what works with your workflow and use case.

However, given that you're in r/homelab, it's reasonable to think you're open to learning new things. With that, Windows tended to not be as stable as Linux (hence the dominance of Linux in the server world).

Windows approach to drivers and software wasn't as clean as Linux. Uninstalling software was not guaranteed to remove everything in Windows.

Windows license is another minus.

Plus, given that it isn't open source, and given the dominance in desktop world, lots of viruses tend to target Windows, and we don't get patches on a timely manner. Plus, there's a history of patches breaking things in Windows.

Linux and Unix, tends to be simple and stable. Synology is a very good NAS, which combines the robustness of bsd with a fantastic GUI. I'd personally urge you to get another Synology or explore xpenology.

But barring that, your use case today is simple enough and if you think Windows is sufficient, go for it.

If you want to also get learning out of it, explore truenas scale. It's based on Debian and is fantastic. You can also sideload proxmox on it for various VM and lxc magickery.

It's a complete misunderstanding of what's going on. The way the scheduler switches applications to ensure they all get prioritized equally was built with 8 cores in mind. All cores were always used.