How to score a dive

You wrote:
How should I annotate this in my score so that I can hear it during playback?

I had a look at the video and it has some guitar techniques which can be notated: which is MuseScore's primary goal - i.e., to produce written scores playable by human musicians. To that end, the scoop symbol is available in the palettes. (In the video, the TAB shows it in measure 7.)
So, regarding notation, you're good to go.

Playback, though, is another matter. Through the years, as MuseScore's proficiency in notation acheived a satisfactory level, playback issues were subsequently tackled, and progress has been made. Nonetheless, work still needs to be done, especially concerning the interpretation of various performance technique(s).

Now... here's the good news.
The MuseScore app is extremely deep in providing accessible controls. It has features that can be used (sometimes intentionally abused), and combined to "force" a desired outcome - in this case nuanced playback of measure 7. Basically, playback success often depends on how bad you want to hear it relative to the effort required.

Have a listen:
surf.mscz

I added a basic drum line to the score.
Also, compare the TAB to the TAB shown in the video.
To see the hidden trickery, use menu item: View and put a check in the box 'Show Invisible' to see where I used bends.
Also, click on the Low E with the scoop in measure 7 and check out the 'Tuning' offset I applied in the Inspector.

More info,:
https://musescore.org/en/handbook/bends
https://musescore.org/en/handbook/inspector
https://musescore.org/en/handbook/tablature

Regards.