@publicvoit @hlegius sounds like good advice, overall. It's easy to get overwhelmed with all the possibilities of org-mode! Even just headings with TAB and M-up and M-down is a pretty useful feature set.
Probably the ideal subset varies between different people, so some exploration of features you'll end up not using is probably necessary.
Myself, I've found the spreadsheet feature useful enough to use orgtbl-mode even in files that aren't in org-mode, and the "evaluating code blocks" feature is one of those things I've been meaning to get around to trying for years.