Best way to reattach rubber stripping around windshield

Any automotive windshield shop can reattach the strip. My local shop fixed one on one of my cars and did not charge. It took them less than 5 minutes. While it was being done, I ran next door and bought them donuts.

There are sealants and there are adhesives, and they will know which to use. Window mounting systems vary. You likely need an adhesive, and the material will need to be cleaned just prior to application.

On a similar note, many exterior rear view mirrors are held on with urethane adhesives. Again, visiting the people who have a urethane applicator, and not having to get large tubes for a small job, makes lots of sense. Again the local shop does them as a courtesy, and in 30 or 40 years I have never paid for a external mirror reattachment.