The JBL Clip2 speaker uses Bluetooth v4.2
Hesh 2 headphones uses Bluetooth v4.0 (guess based on an ad I found)
Hesh 3 headphones could use Bluetooth v5 (since they are newer)
The Ford should be Bluetooth v4.2 based on age (pre Bluetooth v5)
iPhone 7 uses Bluetooth v4.2
Based on this perhaps the phone can only send notifications to Bluetooth v4.0 devices and older. Probably not though. You are seeing inconsistencies with the same hardware.
Apple has not been good with working with legacy Bluetooth devices, my Buick used to be able to make and take calls with the car controls, touch or voice, until iOS 10, which then the car said my iPhone X has no voice control capability. Which is not true as voice control over Bluetooth is one of Apple's advertising points. My Plantronics headset says the same thing. I had to manually dial the phone and then it would connect to the car and I could talk through the car. When iOS 13 came out, it was partially fixed. If I use the power button to initiate voice control (Siri is OFF) then I can voice dial and take calls with the car controls. I can't initiate voice dialing with the car, but I am limited to Bluetooth 4.0 A2DP (no music/podcast streaming only phone calls) and the car no longer recognizes the iPhone X on USB either, when it did under iOS 10. Deleting the phone and re-paring did not help.
I also logged bugs against iOS with Bluetooth, but they don't seem to be resolving them very quickly. The recent no handset laws are making this more important than ever.
Maybe you need to make custom buzzing patterns for Text message notification. Stop depending on Apple's broken Bluetooth support.