This is not about the same unit comparison. This is about whether HDR is worth it? It does not say comparison.
HDR and no HDR comparisons should
always be done using the same model at exactly the same time when you want to prove the HDR efficiency.
When you want to compare HDR of different cameras they
always should be On on both or Off on both.
Comparing A229 HDR with A329 No HDR it is not correct, such video should be not allowed on forum.
Because you are in the USA you should focus more on the Telephoto camera and always HDR enabled. If you want to make a night comparison for car license legibility you should make one like: RTC300 HDR On, A229 Pro HDR On, A329 HDR On, A229 Plus HDR On. Or instead the A229 Plus HDR on to use any dashcam you want with HDR.
If I was american I would always install a telephoto camera with HDR in my car, such dashcams should be standard in the USA.
Right now there is no better camera than RTC300 for USA car registration plates and if you are also a seller of dashcams you should promote a lot this unique feature because until other dashcams manufacturers or other american sellers will see this opportunity you can have a lot of sales before them.
For you, the RTC300 or the A229 Pro Tele 3CH is more important than actual A329. Its a little better HDR compared to A229 Pro is too far away from the legibility of RTC300 which I am sure it is the king of american registration plates.
Because you already have some editing skills and you don't need many time to prepare a video, if I was you I would prepare in the car some 4 dashcams setup which will contain the RTC300 and the other three to be some very popular daschcams sold in USA but not sold by you, for example: Garmin, RedTiger, 70Mai, etc and release videos very often on YouTube, TikTok, to prove that the only dashcam which can read american license plates at night is the RTC300.
But! For the USA the limits of RTC300 should be pushed even more. Right now I consider the RTC300 to be very good for european plates and good for USA. The other cameras with Sony IMX678 are poor for american license plates and the dashcams with no Sony IMX678 are very poor for such USA requirement.