For Linux, using anything (PC hardware) older than 2006 is an exercise in futility or ingenuity, depending on what your parts availability and outcome is. Based on my own experiences and observations of others, the bare minimum "Can I make this work?" config for current mainstream Linux distros is...
1. Quad-core CPU. Obviously, 64-bit and the newer, the better. You can get by with dual-core, but it won't be enjoyable. AMD or Intel, doesn't matter, but most people use Intel unless they have access to newer AMD CPUs that offer a bit of a bump for specific usage.
2. 8GB of RAM. Obviously, the more, the better.
3. SSDs. No more using HDDs, unless they are newer ones.
4. Gigabit Ethernet.
5. At least two USB 3.X ports. You can get by with using full USB 2.0, if that's what's available, but you're gonna want USB 3.x, even if you have to use a PCIe add-in card.
6. The most recent Nvidia or Intel GPU you can get your hands on, with the caveat that it obviously has to be usable with the size and power constraints of the PC. For pre-built stuff, this obviously presents a problem, if you are looking for gaming prowess, but there are low-end options available that fit any PCIe-capable PC. AMD has recently become fairly functional on Linux, so you can go with that too, but Nvidia and Intel are the ones that most people prefer.
With Windows 11 making a massive mountain of e-waste from 2010's era hardware, you're gonna see a lot of (otherwise) perfectly good and usable 6-8 core (or more) machines going to the recycling centers or being repurposed for Linux usage, so it's a good time to start looking for hardware, if you want to get into using Linux.