Buy a new computer or upgrade the current one?

I would like to record videos with OBS and stream them on Twitch without it lagging and the CPU being overloaded. But for that I would also need 32GB ram because I would stream on the same computer that I play on. But now the question: Would it be smarter to improve the current computer or to buy a completely new one. When to improve which parts do I need and when to buy where would you find one with good performance and 32GB RAM relatively cheap?

PS: I'm a noob when it comes to the parts of a computer (hard drive, graphics card and so on).

OEM PCs are not the best for upgrading. The motherboard is some proprietary sh ***, the power supply is some 10 euro thing the ram is cheap, etc. Try to save on a new PC. Either built yourself or as a pre-build.