Pretty much sums it up. I don't feel like renting software. If not, will just stick with the modeling part of this video.
Yes wwrongwright,
There are a few, I have used Quixel Mixer, it's pretty good and there are plenty of tutorials to get you started.
Baking and Exporting Custom Assets in Blender will get you started in preparing models to export and use with Quixel.
Blender along side Quixel Mixer, Quixel Bridge, Megascans, and Unreal, you have a powerful ecosystem.
Thank you for the response. I am a macOS dude and I have tried Unreal. I couldn't adjust the UI to make it bigger to save my eyes from squinting, so I never bothered to learn it. I will give it another go.
Armor paint is $19 for compiled version. It's free if you don't mind compiling it yourself.
Unfortunately I can't confidently say that there is really any one application that is feature-parity with Substance Painter, proprietary or otherwise. However, I think the one's already listed are excellent choices. I wanted to also mention Material Maker if you haven't heard of it, since it's open source as per your question.
It's primarily a tiling material generator, much like Substance Designer is, however it does offer some Substance Painter-esque features. I haven't used that portion of it myself, so I don't know how similar the workflow would be to the videos but if you are looking to try a couple applications, I think these are a couple good options!