Options if it’s to protect against local disasters such as fire:

1. Having a NAS at a family member / friends house as a backup location for your NAS (over vpn) is an option. Works best if they also need an offsite backup with you being able to spare space for it on your NAS in return.
2. Having at least two usb drives as backup locations for the NAS and rotated as often as you think necessary and having at least one stored offsite at a family member / friends house.
3. Rent a proper 1U rack space in the city data centre and setup your own “cloud”, definitely the most expensive option and total overkill if offsite backup is the only reason.

Personally I would probably go for option two and bring the usb drive with me for a weekly coffee with my parents, they’d enjoy the visit and I enjoy knowing that my backup isn’t in the hands of Amazon. I’d go for option 1 if my internet was better.

You will probably want to enable the non-free rpmfusion repository. I can’t remember if that is an option during install, but if not here’s how to do it with the console:
https://docs.fedoraproject.org/en-US/quick-docs/rpmfusion-setup/#_enabling_the_rpm_fusion_repositories_using_command_line_utilities

If you scroll down to Media Codecs and HW Acceleration you’ll have a guide on how to get proper ffmpeg and h264 and h265 driver support:
https://github.com/devangshekhawat/Fedora-42-Post-Install-Guide

Before spending too much time troubleshooting Linux Mint I would try something that’s a bit further along with the kernel updates considering your gpu.
Personally I’ve had good luck with Fedora KDE - https://fedoraproject.org/spins/kde

If you still wanna go for Linux Mint look into how to install the mainline kernel yourself:
https://forums.linuxmint.com/viewtopic.php?t=443810
https://ubuntuhandbook.org/index.php/2020/08/mainline-install-latest-kernel-ubuntu-linux-mint/

As a result I imagine more users will look at other offerings such as Jellyfin.
https://github.com/jellyfin/jellyfin
https://jellyfin.org/