I already built up 3 solar-systems and I can say, it’s expensive and far from easy peasy. The main reason is that you have to do some “hacks” to get affordable batteries. Li-Ion-Batteries are great but simply to expensive and hard to come by as these are from china.
I like to combine AGM 12volt batteries which are used in boats and mobile homes as these are much cheaper and much easier to replace (just visit your local home depot).