2004 Nissan Pathfinder - Holds first shift

First start of the morning or when the engine is cold, first gear revs to 3,500 RPMs (30 mph) before shifting. After that, the shifting is normal until the engine cools… Mechanic’s shop scope showed no error conditions. If repair is too costly, we may decide to buy a similar vehicle. Please provide guidance and suggestions.

Change the transmission fluid and filter. That may make it better, it may not.