MacBook Neo system issues

The symptoms can be approached systematically without assuming a particular cause.

Since you have already updated and restarted the Mac, I would next test whether the problems occur in Safe Mode and in a new user account.

First, check System Settings >> Privacy & Security >> Microphone. 

Apple says apps that have requested microphone access should appear there. Try initiating a WhatsApp call again and see whether WhatsApp appears. (Apple Support)

Next, start the Mac in Safe Mode. Shut it down, press and hold the power button until the startup options appear, select your startup disk, hold Shift, and choose Continue in Safe Mode. 

Then test Safari, Chrome, WhatsApp and Mail again. Apple provides the Safe Mode procedure here: Apple: Use macOS Recovery on a Mac with Apple silicon

You can also create a temporary accountunder System Settings >> Users & Groups >> Add User and test Safari and Chrome there. If the same problems occur in both accounts, that gives us useful information for the next troubleshooting step.

For Mail, check System Settings >> Internet Accounts and make sure your email account is present and that Mail is enabled for it.

I would not erase the Mac or reinstall macOS yet. 

Apple does provide a way to reinstall macOS through Recovery while retaining your files and user settings, but that should be considered after the simpler diagnostic tests. (Apple Support)

Apple's relevant troubleshooting pages are:

If an app on your Mac stops responding, quits unexpectedly, or won't open

Control access to the microphone on Mac

Use macOS Recovery on a Mac with Apple silicon

How to reinstall macOS

Given that Safari and Chrome are both crashing and the microphone-permission list is also behaving unexpectedly, I would start with Safe Mode rather than reinstalling individual applications.

If all else fails, follow the advise from @ jeffreythefrog 👍 and use the Etrecheck application 

Have you tried and boot the Mac into the safe mode to see if the issues persist? If they don't persist they are usually caused by an external piece of software

Start up your Mac in safe mode - Apple Support

+1 for trying safe mode. when I got my Neo, right out of the box, I needed to run it in safe mode for ten minutes before restarting normally. doing so fixed the minor annoyances that it was having.

that aside, are you using any apps that claim to "clean up" or "speed up" or otherwise "optimize" your Mac? and / or any antivirus apps? the only thing those apps are good for is causing major issues within macOS while providing ZERO protection or benefit. you would do well to uninstall them.

If you have no such apps, i’m thinking you should download and run the free version of EtreCheck so we can see if you have some software installed that is causing your issue. make sure you give "full disk access" to etrecheck. Learn how to use it by reading Using EtreCheck. if you need help interpreting the report, you can see how to post the report here by reading How to use the Add Text Feature When Posting Large Amounts of Text, i.e. an Etrecheck Report. and it automatically obscures sensitive things (like serial numbers) so you don't have to worry about sharing the report here.