Not sure if you will get an official response to those "leading questions"
but ...
1. Providing a complete printed manual with a device is no longer a thing and will disappear soon for most. It is not green and wasteful in most cases as people shouldn't really need it if the UI is good and there is a good one-pager Quick-Starter Guide. A PDF download and/or an online manual on their web site will be the way of the future. There is no getting around this.
Of course, in this case it is perfectly legitimate to criticize not having a spec section, not proof-read, not correct obvious/outdated mistakes in the manual provided for download. It is the worst roll-out I have seen of any brand name product.
2. Web UI vs OSD UI. For settings (as opposed to status display), the latter is another thing that is going the way of the DoDo bird. It is very resource-intensive, bug-prone and expensive affair for devices to provide OSD settings menus, especially as the systems get more complicated with a lot of settings. Doing so holds back features/flexibility that can be provided via a Web UI which can also be made much more user-friendly and informative. People are doing this already on things like WiFi routers etc for it to be some new thing that has to be learnt.
Of course, the way Anthem has rolled out the frustrating network connectivity set up on the device to get to that point is inexcusable (especially Wifi as the most common these days compared to Ethernet for the living room) . Why would you ask someone to get Google Home to set up the WiFi on the device? The same mistake as getting PlayFi to set up WiFi on their streamer boxes.
3. As far as I know it has ARC implemented on the device itself but ARC Genesis software running on a computer to do measurements, etc that will recognize this device has not been made available (the last version which seems to have some problems was pulled from their site). This is also part of the botched roll-out.
4. The "superiority" of the AVM 90 over the AVM 70 to justify the price difference is still a mystery. This seems like a product management decision than a technical one to cater to the niche crowd that will pay stupid amounts of money to have the top of the line regardless of whether it is worth it. A revenue management decision.
So, it is a combination of device evolution and the botched release that has displeased potential customers like you.
Typically this kind of mis-management of a product line in any company is precipitated by a bad management change (or hiring McKinsey, Bain type of consultants to suggest cost efficiency measures) not Covid-19 as an excuse. So, I wonder what happened inside Anthem to stumble so badly in this particular launch.
The initial user reports indicate the device itself is pretty good so engineering seems to have delivered. More of a product-management, marketing, top layer issues, it seems.
