What in the heck it deleted my answer.
Ok here is how you do it. P.S. go right to the bottom to discuss only stand alone pages/pages the rest starts at apps and goes down :-) I think you care about the bottom, but this covers all artifacts
You have 4 things to do. Ugg here i am typing it again
1. Share the Page and or the Canvas App
--Go to your Solution
--Go to your Page/Model Driven App and or a Canvas App if you have one its the same Share Process
You can see here, I have a Canvas App and I have a Model Driven App with a Custom page in it.
For the Canvas App just click the ... click share
Type in a name or group.
Then click the Eye ball
Set them as Co-owner, you cannot set the as the ONLY owner not possible
NOW GO TO THE BOTTOM PLEASE
For Model Driven with Pages
Click the ... again (You can see my custom page sample)
Click Share
Type in a name and then click when it shows them so you add to them to the New Section
Then on the right set their Dataverse to at last System Customizer
And done
Lastly dont forget to add them to any roles or SG's that the original owner was in
For a stand alone page you have
Make sure you published all customizations on the solution that has the page.
Go to the Admin Center for that Tenant
Click on Power Apps in the Resources Box
Find your page, click the ... and click Share
And thats how you do t.
Please Mark as the Answer if this helps you and maybe a like
Cheers!