Hi. So, NVIDIA is [mod removed] satan spawn and I need to get rid of it in favour of something more open-source friendly like AMD. How do I go about finding a compatible card? Is there any chance of losing data on my computer or any specific steps I need to take to replace it or can I just pop it in and on next boot it will work? This is on Debian Sid.

I would look into their current lineup of graphics cards and find one that meets your requirements. From there, verify if a driver is available for your OS by visiting AMD's support website (https://support.amd.com/en-us/download) and searching for the card of interest.

Once you get the basics out of the way, do some follow-up research on the card and how it behaves on Linux. Do some general searches on the net to get an idea of what you'll be encountering before you buy the card.

When I'm researching hardware, I like to check if there are reoccurring issues, like if the card overheats or if it preforms poorly on my distro. Getting this out of the way before buying the card will save you headaches.

Make sure your system can support the card. Is your Power Supply capable of powering the card? Does your Motherboard support the I/O configuration (PCI-E support?). Does your case have enough space to fit the card?

Once you have the card, installation should be done with care. I would review a few tutorials online before installing the card.

Over the years I've found it to be just opposite, that is, NVidia cards work better than AMD, and that was after using nothing but ATi (bought by AMD) for 25 years.
OTOH, over the last year of so, there have been some major improvements of the AMD drivers.

What types of issues are you having with nVidia? Work here without issues.

Freezing on Plasma. Specifically, I'm having issues with Nouveau, which are the open source drivers.

^ on debian sid specifically?
tried other distros?

the way i see it, open source drivers for both gpu manufacturers have improved a lot in recent years. some even say open source amd driver is better than closed source.

the closed source drivers seem to be working better from nvidia.

This was also a problem with stable.

@annadane

Please refrain from using obscene language as this is a violation of the LQ Rules
I removed the obscene language in your OP. Any further violation of this type for the LQ Rules then you will receive infractions.