Sad to say that while ASUS might have fixed the radio issue with the 2019 routers they have not solved the other issues.
So, turns out the router
is working properly and the issues you have are software related. We are making some progress here. What exactly you expect ASUS to fix for you? You already send back one router with VPN issues, remember? It was probably perfectly fine unit. Now you have another brand new router, VPN issues again. You had to realize by now that something fishy is happening
around your router. Instead of looking for a solution to a very specific issue though, you just blame ASUS. And you are perfectly comfortable with it, repeating it constantly in every single thread someone mentions something closer to what you have experienced. This is wrong. You have to do some more homework before making conclusions. Let me give you examples why:
1. About your favorite Amazon reviews. If you have noticed, the reviews accumulated there are per product. It wasn't a single batch of 1000 or more units sold by one seller. There were multiple sellers of this same product. Why? Because some people mention "renewed" units, some mention "warehouse sale" units, some mention "30 day warranty", some say "new in a wrap"... just read carefully. It was quite possible someone was re-selling re-manufactured returned units at some point, I wouldn't be surprised. Some authorized service provider or re-seller, for example. I've seen this before on Amazon. It hurts the product, it hurts the customers... Amazon is getting their commission anyway. It's a business in a first place and a good one, as far as I know.
2. About VPN issues. Not all VPN providers play well with this specific model. New hardware, new software, first with hardware processing, first with really fast speeds, went through few OpenVPN versions, etc. ExpressVPN, for example. I can tell you what exactly was not working and that was the reason for me to change VPN providers. If I look back in my records I can even find what the issue was, some setting was enforced on their servers preventing the VPN Client to re-connect and auto-connect on boot. They don't offer officially support for this router anyway, so no issues here. There was no solution provided on their end, I moved to another provider, problem solved. Not an ASUS issue, they have nothing to do with it. I can play the RMA game forever, there will be no change. VPN works very well on 384.9~384.13... tested and used by me personally, for a very long time. You don't need to run 384.14 Alpha to solve the issue.
3. About the scripts you are running. It is quite possible one of them is disrupting your VPN clients. And this one is spdMerlin. By itself it runs properly, but eats all your available RAM every time it runs, affecting other things running on the router in the same time. The faster your ISP speed is, the worse it gets. The more VPN clients and servers you have, the worse it gets. Swap file on a USB stick won't help. I did recently tests with Samba server and large file transfers. It also eats RAM like no tomorrow in some specific cases. I had a swap file on USB3 SSD drive, but it didn't help much either. I've lost my VPN clients 3 times during the test due to low memory, the system just starts terminating processes, sometimes important ones due to no other options. Now, this specific issue is related with ASUS. They offered something in their firmware that doesn't work properly. In your case though, the issue might be wrong script in a wrong time.
Think twice next time before you blame ASUS.
Ask the right questions first and someone here on SNB may be able to help.