How can I merge contact lists on Apple devices?

Recently i transfered to apple device again and got frustrated about how to merge if you can even merge contact lists. My question might be a guide for those who want to merge their lists as well from other sources(e-mails, phone numbers etc).

First i logged in to all my mails that i use regularly including the one that i migrate from. Then in your contact app you might see a couple of list how many contacts are imported from which sources. There is a common list called All contact which already merged, but it is not syncronised (as far as i know) with icloud. So as a next step i created an export directly to a separated folder on the cloud drive and saved the list there.

Then i went to my computer, logged into icloud, went to my drive and downloaded the .vcf file(windows machine). Then went straight into the contact app and clicked on Plus and selected import contact option. Browsed the file opened it and now it's fully synced. If you want you can do edit and sort which contact you need further.

Hope this helps!

[Re-Titled by Moderator]