Airport Extreme/Time Capsule

There is no feedback link for the Time Capsule or other AirPort routers, since they were all discontinued about 3 years ago.

The closest that you will come to Time Capsule feedback is Time Machine feedback.

https://www.apple.com/feedback/timemachine.html

None.. the Airport Utility is UNIQUE to Apple routers.. it is not compatible with any other router made.

All non apple routers use built in HTTP web page and/or a controller with cloud links for mobile phone app or use on computer or special controller box.

Apple airport utility is totally minimalist and has zero serious controls. Like a log so you can find out what is going on. So why do you want to keep using it??

What replacements work with Airport Utility?

If you are asking if AirPort Utility can be used to set up and administer a third party router, the answer would be "no". It only works with Apple routers.

Third party routers will have their own setup utility.......which is often a web based application.

Read the info about mesh systems.. almost all mesh systems use cloud + phone app.

https://dongknows.com/web-interface-vs-mobile-app/

The apple interface for the airport utility is built into the routers.. hence the utility does not require an internet connection.

The vast majority of mesh systems do not have inbuilt controllers .. rather they use a cloud system that each component of the network reports into. This is then open to abuse.

I really don't want my internal network info shared on a server in another country for example.. China particularly but any place that has different rules or different system. BTW USA is not excluded from attacks on those systems.. indeed many are at risk as indeed actually happened.

https://www.itpro.co.uk/security/hacking/358290/ubiquiti-networks-data-breach

There is a middle path.. instead of the controller living on cloud it can be a small box running say linux with standard web access. This could also be hosted on a computer and you can use phone app to access it or any browser at all.

What was good about the Apple system is that it was internal.. no cloud access was even available.. it was developed long before cloud became a thing. A modern equivalent then is available from companies like Ubiquiti and TP-Link that offers a small cheap low power box in the network.. that monitors your system 24/7 and allows system wide changes to rules. You can easily see which clients have used the most internet data etc.. so far more detailed than Apple utility which could have been great with a bit more effort.

I bought the HomeKit versions with security - but they were flaky

You cannot win sometimes.. Homekit will doubtless improve as Apple puts more effort into it.. and manufacturers get firmware better, but it is difficult to keep IP switches online.

I bought a bunch of cheap ones and flashed to Tasmota firmware. To avoid exactly the issue of needing an app based in China. Though it was a lot more difficult than it should have been to flash. It now works very well.. but it needed major changes to the 2.4ghz network to help out.