Unlike the V part of AV, audio starts to cost a bomb as you inch towards better gear.
You can go out and buy an LG or Panny OLED and get literally the best TV on the market for a grand and a bit.
If you wanted the same in the audio department, you'd have to add a zero or two onto that price.
A soundbar will certainly be better than TV speakers, and if you get a surround sound one, will be a great entry into decent audio.
But audio is analog and based on simple physics. There's only so much that modern technology and software can do to improve the basic of a speaker cone vibrating the air to make sound. Small bookshelf speakers through an amp will be able to push more air than a slim soundbar, and midrange and above floorstanders will be a significant improvement.
I've found with audio that once you get to a fairly good point (and point can be met with a good soundbar) that improvements are incremental and get v expensive. It's whether you have the money, space and inclination to buy expensive speakers and amps to chase after audiophile quality.