If you would like to save money though, each part you get comes with detailed instructions and there are thousands of tutorials and help videos online to get you into building a PC correctly. Hardware companies know that many consumers of recent-gen hardware are building computers/upgrading themselves, and most come with very detailed instructions with chat support, etc.
Besides even if you get pre-built, you will need to learn how to build a computer soon thereafter anyway if you want your PC to stay relevant for longer than 3 years, otherwise you are wasting a huge chunk of money.
Some of my parts are over 4 years old yet my computer is very high end, knowing what needs to be swapped in and out on a short timeline or what other components can be used until they die, can be a huge money saver.
Getting a pre-built gaming PC is just stalling whatever learning you will need to do anyway if you plan to stick with PC gaming for longer than a couple years. Better now than an empty wallet later.