If flatpak is working for you then there is zero benefit to building it yourself, it sure as shit will not be easier.
No one can tell you exactly how to build software universally. Each application will have different dependencies, build systems, required compile time configuration options, etc.
There may be dependencies needed that Solus does not have in its repository at which point you have to compile them too which in turn might have their own dependencies not in the repo, so on and so on making a seemingly simple task much more difficult than it first appears.
Projects rarely have 100% accurate build instructions to the point I don't even bother looking for them any more. I work it out by looking at its build system files and compile errors.
Applications sometimes need patching because upstream have not tagged a new release that addresses a critical issue.
Sometimes building a certain application is a massive PITA because it has a difficult build system or development practices such as only supporting building with the latest working git build of a compiler, so you need to patch the absolute living hell out of it to make it work. Sometimes you can find patches someone else has made to fix the issue other times you are creating the patch yourself because you are the first one to encounter it. Perhaps because your distribution is one of the few using a newer or older version of a dependency...
If Solus updates a dependency the application you built uses and it has ABI changes then you need to recompile it against that updated dependency otherwise it stops working or may not contain a security fix.
This is all worst case scenario stuff, not everything is that difficult but you never know until you dig in to that specific application. This is not to dissuade people from learning/contributing, just explaining it is in no way shape or form the easier option.
I started contributing to Solus as a package maintainer in order to help out and free up staff to work on other things. If you are going to go down this path it should be to help out or satisfy your own curiosity. Otherwise you are just wasting your time.
