Best practice to update angular within running project

Hey guys,

I really tried my best with google but gave up just now.
I have upgraded my project to ionic cli to 6
MY ionic info looks like this


Ionic CLI : 6.12.1 (/Users/henningjaeger/.nvm/versions/node/v15.0.1/lib/node_modules/@ionic/cli)
Ionic Framework : @ionic/angular 5.0.5
@angular-devkit/build-angular : 0.801.3
@angular-devkit/schematics : 8.1.3
@angular/cli : 8.1.3
@ionic/angular-toolkit : 2.0.0

In my package.json it states
@ionic/angular”: “^5.0.5”,
@ionic/cli”: “^6.12.1”,

Now I wanted to install firebase but that isnt working because of my package.json having those
@angular/common”: “~8.1.2”,
@angular/compiler”: “~8.1.2”,
@angular/core”: “~8.1.2”,
@angular/forms”: “~8.1.2”,
@angular/platform-browser”: “~8.1.2”,
@angular/platform-browser-dynamic”: “~8.1.2”,
@angular/router”: “~8.1.2”,

So i thought: Ok I will update those.
But it seems that is not the right path and I am going at it from a wrong angle.

try 1: Uninstalling the @angular packages and reinstalling them
try 2: npm update

will land me with
[Cannot read property ‘match’ of undefined]

I am pretty sure I am missing some basic understanding. So my question is:
What is the best practice to upgrade an angular version within a ionic project?

I would say the same way recommended for any Angular project.

Good then i did the right which is not working.
So my crappy solution to help myseöf was to create an all new ionic project and migrate all my code there. 2h manual work questioning the upside of dependency management in the first place :frowning:

I was basicall asking this question because I read here in the forum from the staff an old entry saying one shouldnt upgrade to a non supported version since it hasnt been tested against. So i thought there might be some other best practices

Anyway thanks for letting me know that there is no other way.