Best way to transfer Waypoints and routes

So I know there's a few topics similar in nature but most are very old so software has moved on hence asking the question.

The question is a simple one really but I suspect the answers will not be as simply.

What is the best way to transfer Waypoints/Pois  and routes to the fenix watch?? Not the caveat is this, It has to be done WITHOUT an WIFI / Data connection and must not use the pathetic Explore app(who in the right mind actually thinks this is good is beyond me)..  The reason for the question is  several times recently I have been in the mountains working and could not transfer a damn thing to the watch as The apps require you to have a frigging data connection even though I was creating and sending to the watch from my phone via bluetooth.  Why you must be connected to the internet is a damn stupid idea and effectively kills part of the functions of the watch..

So please share your thoughts and suggestions with why you do it that way.. Hopefully it will help me and many otheres.

thank you

regards

Crags