How can I remove all other apple Ids and use my iCloud apple id

Did you setup your iCloud account using that gmail account AppleID originally? If so, the iCloud email address is a synonymous login to that same AppleID.

When you create an iCloud account using a third party email address AppleID, the iCloud email becomes simply an alternate login ID to the same AppleID. And if any legacy @me.com or @mac.com addresses came along with that, they too are simply alternative login IDs to the same AppleID.

I can use my private email address, my @icloud.com address, or my @me.com email address to login, all to the same AppleID.

You can just stop using the Gmail IDs. You can try setting up Family Sharing between the IDs if you want to be able to share purchases made with the IDs.

Family Sharing.         

Family Sharing - Set up.       

All purchases made using an Apple ID are tied to the ID. Delete the ID and you will need to download them using your new ID. Make sure you sign out from the places in the 4th link before deleting the ID.

How to delete your Apple ID account.         

Apple ID – How to Delete.        

Delete Apple ID (new).         

What to do after you change your Apple ID or password - Apple Support