Alternative theories
1. Someone attacked her as she was dialled in to her work call, on or near the bench, and managed to take her to a nearby vehicle or other location before leaving the area. I suspect this is why they are still seeking witness reports and asking for dashcam. imo this is an unlikely scenario as it relies on a shockingly blatant attacker who chanced their luck on there being no witnesses. If you wanted to kidnap someone there are probably much less risky ways to do it than in broad daylight during a time where lots of people are walking their dogs in the area? If they managed to lure her to a vehicle (willingly in some way) then why did she leave her phone and the dog? What reason could someone give that would make you leave your dog off lead, your phone on a bench, and wander over to their waiting car for a moment??? I’m not sure the distance to the nearest place one could park a car, or if that aligns with the area with no CCTV, but I suspect it’s too far to be dragging someone unwillingly?And surely the attacker wouldn’t have full knowledge of CCTV coverage anyway? Doesn’t seem plausible at all to me.
2. She has decided to go missing or killed herself. This also seems unlikely to me; close family members do not seem to support the theory and they will know her best. Women are (largely, but not exclusively!) nurturing and I don’t think she’d have taken the dog with her if this was her intention. Oh and she arranged a play date with a friend minutes before the incident, which seems to indicate that she was planning ahead in a very routine manner.