Changing site url problem

Hello.
I’m tryng to change the “site url” only (not the WP installation directory) from http://lnx.mydomain.com/wp to http://www.mydomain.com.,
leaving the installation directory in http://lnx.mydomain.com/wp
I’m following wp guide at this link https://codex.wordpress.org/Giving_WordPress_Its_Own_Directory.
at the and of the process everything seems ok but i’ve got this strange problem: i lost social icon in the menu and footer.
I’ve used theVelvet Blues Update URLs plugin to restore the broken internal links adn it was ok, (i just did not check the option to update the GUIDs, should I?) but i’ve still the problem with social icon as with the back to top page arrow and the hover arrow to open portfolio element in portfolio grid.
All these problem are in the front end.
In the back end everything seems to be ok except for the page aspect/personalize that lost my log in and if i insert user and pw it keeps to ask me the log in.

If i come back to old site url, and delete frome the root site .htaccess and index.php file, everything come back to work properly.

I’ve read many guide for this process and i can’t find any solution.
Could you help me please?

Thanks a lot for your collaboration.
Best regards.

Giuseppe.