This site can’t be reached...Checking the proxy and the firewall

You mean Brave is crashing on both still?

Have you restarted your router or Modem?

Make a New Location, Using network locations in Mac OS X ...

http://support.apple.com/kb/HT2712

System Preferences>Network, top of window>Locations>Edit Locations, little plus icon, give it a name.

System Preferences>Network, click on the little gear at the bottom next to the + & - icons, (unlock lock first if locked), choose Set Service Order.

The interface that connects to the Internet should be dragged to the top of the list.

Sys Prefs>Network>highlight the Interface you're using>Advanced>TCP/IP>Configure IPv4: Using DHCP.

If using Wifi, instead of joining your Network from the list, click the WiFi icon at the top, and click join other network. Fill in everything as needed.

System Preferences>Network>choose interface>Advanced>Proxies Tab, make sure none are set, like for HTTP & HTTPS.

System Preferences>Network, unlock the lock if need be, highlight the Interface you use to connect to Internet, click on the advanced button, click on the DNS tab, click on the little plus icon, then add these numbers...

8.8.8.8

8.8.4.4

1.1.1.1

9.9.9.9

Apply.

Delete these files & Restart...

/Library/LaunchAgents/com.paragon-software.ntfs.notification-agent.plist

/Library/LaunchDaemons/com.graphisoft.TeamworkServiceProcessManagerAgent-v23.0(Manager-2020-06-02).plist

/Library/LaunchDaemons/com.graphisoft.TeamworkApplicationServerMonitor-v23.0(Server-2020-06-02).plist

/Library/LaunchAgents/com.graphisoft.BIMcloudMonitor.Server-2020-06-02.plist

/Library/LaunchDaemons/com.graphisoft.TeamworkServiceProcessManagerAgent-v23.0(Server-2020-06-02).plist

/Library/LaunchAgents/com.graphisoft.BIMcloudMonitor.Manager-2020-06-02.plist

~/Library/LaunchAgents/com.adobe.ARM.***.plist

This last one...

~ tilde indicates hidden Home Library.

Apple hid the Users' Library folders...

Method 1:

1. From the Finder, select the Go menu at top of the screen, and choose Go to Folder.
2. In the window that opens, enter ~/Library, and click Go.

Method 2:

1. Go to the Finder (or desktop).
2. Hold the Option key on your keyboard, and click the Go menu at the top of the screen.
3. With the Go menu open, you'll notice that pressing and releasing Option will display or hide the Library choice in this menu.

 4 Select Library from the Go menu (while holding down Option) to access the hidden folder.

This is pretty bizarre !

EtreCheck is a simple little app to display the important details of your system configuration and allow you to copy that information to the Clipboard. It is meant to be used with Apple Support Communities to help people help you with your Mac.

https://www.etrecheck.com/

Pastebin is a good place to paste the whole report if you capture the URL while there…

https://pastebin.com/

Workable but harder for me to work with...the Note tool on the bottom of this editor's toolbar, as shown in the image, to copy and paste the output from EtreCheck. In a Reply before you click post, look for this to add longer texts..

Have never seen MWB interfere with anything, but a new download crashing points to some other serious problem.

Safe Boot from the HD, (holding Shift key down at startup), does the problem occur in Safe Mode?

Safe mode attempts to repair Disks & clears lots of caches, so if Safe Mode works try again in regular boot.

Try another download of Brave.

Are you running any VPN, Anti-Virus, or Cleaning apps?

Try this browser as a test...

https://brave.com/