To me it doesn't add up that this was foul play. Any nefarious scenario would be such a stretch in my mind, whereas accidental drownings in cars occur more than once a day in the US (400 avg. annually).
A 24 year old who realizes they don't have their cell phone is going to struggle to function and be in complete panic mode. It was her first day driving (in awhile at least), and her first day driving a new car. She didn't have her phone for GPS or maps, and she may have thought she was following someone and ended up following the wrong car in the wrong direction. I think it is possible the GPS malfunctioned after the car hit the water. I also think she could have accidentally lowered the rear window when trying to escape from the car as it sank. It would have been impossible for her to open her door due to the water pressure and I hit the wrong window button all the time in my car. She had been pregnant and sober for a significant duration and her alcohol tolerance was probably down. I personally do not think she was black out or even necessarily drunk. But we do know she had drank and was probably somewhat impaired, even if minimally.
LE has been so tight lipped. I think people have given them way too much credit as well. I doubt they are scrutinizing every word that they state on this matter as much as everyone here is. Saying there is no woman abductor out there can seem strange to us, but it's extremely common to alert the public on whether or not there is a threat. He may have gone home that night and thought, "man, I should not have worded it like that." We don't know what LE knows, we don't know what DW told them. We don't know anything from them, really. Even if they knew whether it was 2 or 3 cars, and even if they knew every person's identity, and even if they knew whether the timestamps added up, and even if they knew certain things about her impairment levels or mood, this LE dept. was not going to tell us. The public interest seemed to make them want to play things even closer to their chests, IMO. They are under so much scrutiny that their behavior makes sense to me.
IMO it's dark, she's freaking out and feeling naked and alone without her phone, she isn't used to driving, she isn't used to navigating roads, she is at least a little impaired, and once she realizes she's lost she probably starts panicking even more. Even being lost and alone as a young female is scary. She stays on the road and doesn't hit anything, sure. But even perfectly sober, non-panicked people who have their phones accidentally drive down boat ramps sometimes. In the dark it looks just like a road often until it's too late.
JMO
It's really sad to say, but this happens more than we think. Some examples from just the first page of a Google search:
2 women, one pregnant, dead after car drives off boat ramp
Narrows Marina boat launch: Dark, deadly and unregulated
Mystery surrounds woman who drove off Lowry Park boat ramp
Man dies after driving SUV off Port Jeff boat launch (quote from this one: "The incident marks the fifth time someone has driven into the harbor in recent years and the second fatal accident at the boat launch in the past six months." This is just ONE boat ramp!)
Leon County aims to improve boat ramp safety after deadly crash
Motorist sinks car in Lake Ontario after mistaking boat ramp for driveway
https://www.caseyshomolaw.com/womans-death-prompts-fort-lauderdale-boat-ramp-warnings/