Google Analytics - tracking multiple website

hi guys, I have so many domains and subdomains, it started to be a real pain to track them all separately on google analytics by using separate tags. I am assuming there is a solution to track them all in once based on what I found in google. Can someone please show me how to modify google analytic tag for each domain so that I can see everything in one place.

Note: I still need to see the data of every website separately. So same code in every website shouldn't work.

Thanks

Google Analytics can be a little tricky for customization, but it should work as expected.
Few options:
1. You have Custom Channel Groupings - Each Channel can be a separate domain

2. Cusom Parameter - i.e. an additional utm that you can call: "utm_domain". For that option to work, you will need a script on your sites that reads the landing URL and append to the end of the url, utm_domain=domainname.com
So even if you use utm parameters to track your campaigns, the custom utm would be added at the end.

Then you can select in acquisition view, the dimensions you'd like to see - in this case utm_domain and you'll see the list of domains and associated traffic.

I'd suggest take this course, grab it totally free nowadays.
https://www.udemy.com/google-analytics-to-do-list/learn/v4/overview