* edit-- not that it looks all that hard, just the sheer amount of things to learn makes it daunting.
I've been at it for over 16 years, and I'm still learning new stuff surprisingly often
After many years of using Emacs every day, I decided at one point to throw away my .emacs file and start from scratch. You know, it's a little bit like the old saying about how you should code every program you write twice: once to learn how to do it, and then a second time to get it right.
I had been using Emacs for a while but especially when I first started out, I was maybe as overwhelmed as what you describe. And so I probably did too much, tried out too many things. But hey, that's how you learn, right? After many years, I had acquired much more proficiency, found out by experience which things are essential and which packages that I had installed I actually didn't really need.
And so I made a completely new, empty .emacs file and manually added only a minimal number of configuration options (carefully avoiding copying anything over from my previous .emacs file -- the temptation would be too great to put more than I needed).
Of course since then I have added more and more stuff over time, but I still strive for keeping my .emacs file small. It's not so much an irrational ideal as it is an attempt at keeping it manageable. And so sometimes when I open my .emacs file for some new option or whatever, I use the opportunity to also go over the file and reconsider its current state. More often than not, I end up throwing a whole bunch of stuff away again and make the file smaller and simpler.
A lot of features that Emacs offers through various packages are convenience features. They're great. But they're not essential. Essential is stuff like `(blink-cursor-mode 0)` (I would go nuts otherwise) or `(global-set-key (kbd "C-w") 'backward-kill-word-or-region)` which has become muscle memory to me. Themes and other visual goodies are less important.