how to install a normal browser, not edge

As mentioned you can't because you aren't talking about a computer here

It's a custom os a d don't run exe.files

Firefox or opera don't have Xbox runtimes

Everything that needs to run on a console requires a proper runtime program

Computer programs can't just be inserted without a runtime

Consider it fortunate series and Xbox one are the only next gen console with a modern browser

Ps4/5 is based on the ancient webkit

Whereas Xbox is based on chromium edge for better compatibility with substandards them even chrome which is saying alot

You even have html 5 websites dedicated to play html5 games on xbox

Consoles aren't computers as mentioned if you are trying to do something that isnt meant for consoles like installing unauthorized mods then it's a no

Consoles are sandboxed for a resson

Even sony learned the hard way by allowing unauthorized zero day bugs (hacked vitas)

I normally use Microsoft Edge as my alternate browser.

With the latest dashboard update you should have Edge browser installed on the Xbox 360. You don't install Internet explorer or Edge, they come preinstalled and they can't be uninstalled. Please look for it in the apps list.

Xbox 360 does not support the Edge browser, so it cannot be installed. I believe Xbox 360 has the Internet Explorer browser still available.

I have also seen youtube videos that say how bad EDGE is, and it is so bad that there are programs out there designed to REMOVE Edge from Windows PC's. If Edge was designed for Windows PC's or XBOX 1, it was poorly designed, and leaves you wondering what
Microsoft was thinking - They simply could have allowed IE 11 to be installed and forget EDGE - ESPECIALLY when Edge does NOT have any support for add ons or seems to be incomplete - I would NOT use EDGE for anything - Give us a Real Browser!!! NOT a Broken
down, non-working, crippled version of a new browser which does not work!!!

Thank You!

Brian