Driving a 8Ω speaker from a 3.3v DAC
You will get the best results if you use a Class D full-H driver.

More here: https://www.analog.com/en/analog-dialogue/articles/class-d-audio-amplifiers.html

And here: https://os.mbed.com/users/4180_1/notebook/tpa2005d1-class-d-audio-amp/

Also, consider using a 4 ohm speaker instead.