Since new themes use Bootstrap, the suggested approach for tooltip is to use
Tooltips from Bootstrap
However, arrows are missing on the tip when I hover over the text.
I created a test survey consisting of just one question of type "display text" with content:
<a data-bs-toggle="tooltip" href="#" title="Some tooltip text!">Hover over me</a>
Oops--now I see the problem as I look very carefully. The arrow is there, but very hard to see (on my screen) because of the similarity in color between the popup text (with the arrow) and the background color of the question text.
I just have to pick a better set of colors for the different items.
Thanks for your feedback which caused me to take a closer look.