First, the Galaxy S21 Ultra is probably the best smartphone I've had to date.
That said, I do have a major issue that the Bluetooth audio features that are built into the Qualcomm Snapdragon 888 chip (i.e. Snapdragon Sound) are not being enabled by Samsung. While I have the Galaxy Buds Pro which sound good, they are not comfortable enough for me and the battery life is too short. I want the option to use other earbuds that utilize the latest technology that the S21 is capable of providing. A bit off topic from the Galaxy S21, there needs to be a better selection of ear tips for the Galaxy Buds Pro. In my case, I would like to try a smaller option to those provided.