While I don't play 2024 rules, I'll briefly chime in on save or suck spells in general: I love them!
BUT... (huge BUT!

)
The effects need to be tempered with the spell level (or tier really) and DM adjucation.
2nd-level
suggestion just making the ally walk away? No. It is too powerful for a 2nd-level spell IMO and has been an issue on boards before.
Another issue is the new wording in 2024. In 2014, the DM decided if the request was "reasonable". Having the half dragon leaving its ally/master in a time of need is NOT reasonable. But, in 2024, the wording actually specifies "Stop fighting, leave this library peacefully, and don't return" as an example! This sort of puts DMs in a bad situation because now the very example of what the spell can do compels the DM to allow it. It is another case where the text in the rules is trying to tie the hands of the DM.
Nothing against this obviously, but why did the black dragon breath just hit one PC? Just curious about the encounter layt out.
Does it trigger OA in 2024? I thought forced movment trigger them?
Wow. It never made any save triggered by the damage it was taking?
Finally, another issue with save or suck spells is creatures (particularly) not having saving throw proficiencies sometimes.
Ultimately, any saving throw spell or effect can cause issues. When I was playing a 5E game a few years back the DM pulled particularly nasty combos with a Beholder. Two PCs died in two rounds. Even with random rolling for the eyes, one PC failed vs. Petrification twice (rounds 1 and 2)--turning to stone, and then was auto-Disintegrated (that same round). The other PC was Paralyzed next round (3), and then (in the same ROUND) double whammied with auto-failing Death Ray and Disintegrated for over 100 damage. We eventually won, but two PCs reduced to dust made it a hollow victory indeed. It was a series of lucky eye rolls by the DM and targeting PCs with weaker saves. But hey, its a fragging beholder and meant to kick ass, so none of really complained about it.
But, after that the DM decided to randomly order the eyes and require all 10 be used before any could be repeated in future games.