Is there any way to Open Specific Record Type page layout from Lookup field New Record Creation "+ New Record" option in Lightning Experience?
Thanks, Lalit
There's no option to configure anything to allow User to be redirected to a particular record type page layout while configuring the lookup field. As long as a profile has access to record types for that object which is being referred in the lookup field, while creating a record for that object, you get to choose a record type while creating a new record from the lookup field.
One of the options that can work here is to restrict the User to only have access to a particular record type using profile/permission set combinations. So whenever that User clicks on the "+ New ..." option, the User is directly navigated to the record type page that they have access to.
If that's not an option, you will need customization here then.