Do i really need a Super-Computer to edit Videos? I wanted to edit a video and encountered some severe lag and preview stuttering.

I started looking around on the internet, but I'm just not getting any definitive and practical information on anything.

You'll read about how you need at least 32 GB of RAM and a 4 figures CPU to edit at all.

And others on forums say they edit HD videos on old machines with 2 GB RAM with no issues. 

I'm running Windows on a SSD drive with an Intel i5 quad core (2.8 GHz), 8 GB of RAM, and an NVIDIA 1050Ti 4 GB GPU.

The videos I'm trying to edit are 1920×1080 30 fps (captured with a USB capture card from PS4 and
encoded with Handbrake) they are 1-2 h long (I have many of these videos and I also put them together in a few videos that are like 10 hours long but I don't know if I should use them to edit; I don't know if it makes a difference if a have many small files or one huge one)

I used DaVinci Resolve, Lightworks, VSDC and Shotcut and every time its unusable. On shotcut just playing back a clip and looking through it works kinda ok most of the time but when I cut together some clips and want to see how it looks it starts to lag beyond being usable.

I know that Video editing takes a lot of horsepower, but is it really THAT much? 
I can't imagine that everyone, every student or just your average Joe who's doing their gaming montages and stuff for YouTube in their free time is sitting on a 2000 bucks high-end PC. 

I've read about “Proxy files” for editing, but mostly when people are using 4k videos and even if not, creating lower quality versions every time for every video seems so unpractical.

I don't know, I really didn't think Video editing is so inaccessible. 

To add to my confusion: 

A view months ago I was editing videos with almost the same specs, the only difference, they were captured from switch, on the exact same PC. But at that time I was running Linux. And I used DaVinci Resolve and I don't remember having any issues at all. And I didn't use anything like proxy files or reducing playback quality, etc... 
I think maybe somethings wrong with my windows but with all that conflicting information I just don't know and I hope someone can help me here. 

One thing I want to add: these Videos are kind of big. 2h long video with 8 GB, and they have a bitrate of around 9000.

I don't know much about video stuff, I know bitrates influence quality, but that's it, is 9000 much? Or can you reduce it without a huge quality loss?

Thank you very much!
Research how to use proxies. Proxies are copies of your original footage encoded at lower resolution, lower quality, or just in a less processor-intensive codec. You use them while you're working on your project, and then swap back the high quality files when you do your final export. A bit like offline and online video editing from the days when dinosaurs ruled the earth.

In your case for example, avoiding h.264 will probably speed things up. H.264 does a good job of making really small files at high visual quality, but it's awful for editing. So if you encode in an all-I-frame low-bandwidth codec, e.g. ProRes Proxy, or DNxHR LB the performance should increase markedly.

You can get away with much lower-powered hardware by using proxies, and you don't lose any quality in the process, because you go back to your originals at the end. A good guide, specific to the Resolve workflow, can be found here.