Soundproofing interior doors - door openings too large

Hello Forum,

we have a sound problem with two of our interior doors (children's room and bedroom). Both doors let through a lot of noise; it is almost as if the door were not closed at all.

Both doors are solid core slab doors from Hörmann. The problem is the too large door openings. In both door openings, masonry had to be removed before the door installation, so the gap between the door and the masonry is now 3 cm on one side (and 1 cm on the other). We have already stuffed hemp insulation wool into the gap afterward (not too tightly). Subjectively, this has brought little improvement.

Are there materials we can fill into the gap that can insulate sound better and are harmless to health? We have a controlled residential ventilation system, the gap under the door is sufficient for ventilation, but we would prefer not to fill the gap with rock wool, which is then always in the airflow of the controlled residential ventilation.

Would, for example, compressible tape (for window construction) be a good idea? Are there other options?

Are there materials that we can fill into the gap

Brutally fill with suitable expanding foam all the way into the last corner.