You can use this to connect your TV to bookshelf speakers through an optical cable. Just need some speaker wire or banana plug cables to go with it
This one has HDMI ARC which most sound bars use for connection along with optical
Then offerup/craigslist/marketplace for used bookshelf speakers. Practically anything will be far better than your TV. Like $50 used polk, klipsch, and sony speakers are real common on the second hand market. They may be old but speakers last a real long time if you're not blasting them at super high volumes. Go for speakers that have 5.25"-6.5" woofers. You'll appreciate them for music too
There's a bunch of brands and you really can't go wrong compared to TV speakers. Edifer powered speakers don't require a separate amplifier. Other major brands like ELAC, Kef, wharfdale, paradigm, ...