I tried getting into western classical music several times, but always aborted. I find it really difficult, as it is so diverse and complex, yet beautiful and satisfying at the same time.
Its vastness is astonishing and is the main reason why I always stopped. Where to start? Why? How does it all connect? There are so many more angles to western classical music than one would think.
There are a couple of ways to cut it up, for instance you could segment by:
Mood
Form
Period
Instrument
For me, I started with solo piano mainly, and some light chamber music and worked through periods (at a natural rate rather than any rigorous scheme). I found solo piano somewhat easier to analyze by ear and deliberately stayed away from things like symphonies as they were way too complex to appreciate to a depth that I am personally inclined.
Once I developed an ear for periodic styles and musicianship, it became natural to branch out into orchestration and more composers.
In terms of solo piano works that are famous:
Bach Goldberg variations/preludes and fugues/english and French suites
Mozart piano sonatas k310-333 are decent.
Beethoven piano sonatas pathetique, moonlight, les adieux, appassionata, waldstein (maybe also hammerklavier)
Chopin nocturnes, waltzes, preludes and sonata 2
Debussy - arabesques, suite bergamasque, piano pieces, preludes
This is not the way the cogniscenti would suggest it, but I would look at some 'classical hits' type playlists. These tend to give you a variety of fairly melodic and easy to grasp excerpts from longer pieces.
Find some that take your fancy and then listen to the whole piece, to see if you like that. Rinse and repeat.
Oh and Holst's The Planets is a nice varied introduction to things with some rip-roaring tunes and interesting orchestral effects. Try that.
It sounds like "Hooked On Classics" was made for the likes of you. These albums consist of medleys of selections from classical music. You're bound to hear music you like, and especially music you'll recognize (I was obsessed with old Warner Bros. cartoons when I got my Hooked cassette and recognized much of the music from those), and you can look up the piece title and composer in the liner notes to discover more once you find something you do like.
Hooked was also often used in schools to get kids interested in classical music.
It is vast, you are right. But it is not all a sacred tome. There are a lot of different styles of composition, some which you, depending on tastes, will simply not like, just like any other music.
The mainstays of popular classical music, Bach, Mozart, and Beethoven all practically defined the 3 main "periods" of the genre; Baroque, Classical, and Romantic respectively (though Beethoven is often considered as somewhat of a bridge between late classical and romantic, details..). Thus each of these periods has a unique character and sound, which is as distinct as different genres of modern music, despite mostly using the same instruments.
It is unfortunate that all that variety has been slapped the label of "classical", and somewhat ironic, considering the Classical period of classical music was seen at the time as a reaction to the "overly complex, aristocratic", style of baroque. It was the pop music of its day, now of course regarded as somewhat elitist.
Anyways, I'm somewhat of the Glenn Gould opinion that Mozart is mostly trash (though his keyboard concertos are pure gold). I suppose the wannabe elitist in me gravitates towards baroque, it's intricacy, specifically counterpoint. If the idea of multiple independent melodies playing at the same time, transforming and complementing each other like some kind of musical puzzle fascinates you, as it does me, then I'd suggest binging on some sweet J.S. Bach. You've surely heard BWV 565 at least once every Halloween, and a few of the Brandenburg's. I'd suggest listening to some of his keyboard works, which are easier to digest and comprehend the contrapuntal melodies than some of the orchestral works. Two Part Inventions/Sinofas, WTC I && II, Goldberg variations, etc. Youtube will provide. A lot of these songs are very energetic, with a steady driving beat that you could dance to if you didn't care about getting made fun of by your friends. There's an almost classic VGM style to some of it (or maybe it's the other way around..).
But this is all just like, my opinion, man. Point is to find a song that you like, find who wrote it, and then find more from that same person. Then expand to their contemporaries. If you hear something that does not appeal to you, even if it is a purported super classic, move on. The popular classical music that literally every body nowadays has heard, tend to be shallow and trite examples of what the composer produced in their time (Beethoven was reportedly quite peeved even then that so many obsessed over the Moonlight Sonata. "Surely I have written better things"). Dig beyond the stereotypes and you will find some real gems.
Classical music is a literal treasure trove for those who enjoy instrumental music, and even mad guitar solos (piano was the guitar of the day. The level histrionics, hype, and raw skill demonstration that can be achieved on the piano keyboard can be truly mind blowing. I've always been a big fan of guitar solo legends, David Gilmour, SRV, Eddy Van Halen....but damn. (Check out the cadenza in Brandenburg 5 [1], or almost any Liszt piano solo [2])
I don't know much of classical music, but browsing around I also found some of the Two Part Inventions you mention. Listened to a couple of them, played by two different pianists, and wasn't overly impressed. Then found her playing them, https://www.youtube.com/watch?v=mFKbmBPaeus, thanks youtube, and I was blown away.
Its vastness is astonishing and is the main reason why I always stopped. Where to start? Why? How does it all connect? There are so many more angles to western classical music than one would think.
So thank you for this! I will try again.