We have a collection of old maps. My wife also has a collection of old documents.
Their preservation is difficult and fraught with peril.

Do not laminate your map with any kind of glue, adhesive, varnish, acrylic whatever.

I would take a sheet of Styrofoam from the Home center, and then shrink film it with a plastic film kit that you use for a patio door.
Put the sticky tape on the back of the foam, center up your map, and use a hair dryer to shrink it tight. Work wrinkles out from center.

Out there doing it best I can.