Garmin’s InReach products are great for this. Emergency button, two-way texts, all satellite based, so basically full global coverage. They can also allow you to share your semi real-time location with friends and family, if that’s useful to you.
Unfortunately you will not find a satellite comm device without some kind of monthly service plan, it's how they base their business models.
Get the Garmin inreach, it is absolutely worth it and two way communication is critical in a real rescue situation.