Most emojis dont display at all in the picker, and display as a diagonaly striped rectangle when inserted in the text (which requires clicking a blank square in the picker).
It looks like if it requires some specific font but that font hasnt been installed.

On Ubuntu 22.04 LTS.

Example :

• all "smile" emojis appear well except the last one "🙂"
• 🤓 appears blank (and most of the proposed emojis)