Cross Canonicalization for domains with same menu

[Shrine.SEO.Gal]

I have a client who took 3 pages from its main website and made them into their own domains. So that now, for example,
www.mainsite.com/page
redirects to
www.page.com

This is so users can be given access to the content on that specific page with ease.
Now, www.page.com has the same menu items as www.mainsite.com, so that users who select the menu items on www.page.com will be circled back to the main site.

But this means that there are now different URLs for these pages.
ie:
On www.mainsite.com there is: www.mainsite.com/menu-item
(the content resides here)

And on www.page.com there is: www.page.com/menu-item
(Which is basically "scaffolding" to support the page and a means to get around, so to speak.This is to make any and all pages accessible at either domain. ) I have only seen this type of URL on the Moz campaign crawl. In the real world, when a user selects a menu item from the www.page.com, it will circle back to www.mainsite.com/menu-item

SEO-wise, should I use cross-canonicalization to point www.page.com/menu-item to www.mainsite.com/menu-item? Or would this be splitting hairs since these are only seen on the Moz crawl?

[CloutsySMM]

@Shrine-SEO-Gal said in Cross Canonicalization for domains with same menu:

I have a client who took 3 pages from its main website and made them into their own domains. So that now, for example,
www.mainsite.com/page
redirects to
www.page.com
This is so users can be given access to the content on that specific page with ease.
Now, www.page.com has the same menu items as www.mainsite.com, so that users who select the menu items on www.page.com will be circled back to the main site.
But this means that there are now different URLs for these pages.
ie:
On www.mainsite.com there is: www.mainsite.com/menu-item
(the content resides here)
And on www.page.com there is: www.page.com/menu-item
(Which is basically "scaffolding" to support the page and a means to get around, so to speak.This is to make any and all pages accessible at either domain. ) I have only seen this type of URL on the Moz campaign crawl. In the real world, when a user selects a menu item from the www.page.com, it will circle back to www.mainsite.com/menu-item
SEO-wise, should I use cross-canonicalization to point www.page.com/menu-item to www.mainsite.com/menu-item? Or would this be splitting hairs since these are only seen on the Moz crawl?

For SEO, using cross-canonical tags would help consolidate authority and avoid potential duplication issues, even though the structure is primarily for navigation and redirecting users to the main site. Adding canonicals from www.page.com/menu-item to www.mainsite.com/menu-item signals to search engines that the main version resides on the main site, which is helpful in the long term.

Since these URLs show up only in Moz crawls, this isn’t an urgent issue, but canonicalization helps clarify the content's primary source if search engines eventually pick up on www.page.com/menu-item. You might also want to set up redirects on these scaffold URLs if they don’t need to be indexed separately, which can further ensure consistency.