a common complaint with people who purchase carpet is ” I never saw seams in my old carpet”
it is really the salespersons fault or the installers fault for not preparing you.
Perhaps a wider carpet was used in the old place, perhaps the older carpet was thicker, perhaps the older carpet was matted and crushed and untwisted, and helped hide the seams, perhaps the rooms were smaller.
All that need to be done, is check to see if it was row cut and that there is no tufts trapped in the seam, and latex would be a good idea too.
If it was done to industry standard, then there is nothing more that can be done.
*** “One floor expert to rule them all!” ***