There are two issues here that the OP brings up. First, is his lack of training. Anybody who goes offshore and is days (at least) from in-person medial assistance who has not gotten at LEAST basic first aid training is just irresponsible. A professional Captain or a Wilderness Guide has training, so should you because you are responsible for the crew on your vessel. If you don't know what to do, the best medical kit on the planet is just a pile of expensive ballast.

But... most first aid kits sold to consumers are pretty worthless for vessels that are not within hours of land. Some of them have good bones, but still lack a lot of necessary stuff, and have a lot of filling you pay for that isn't really much help.

Any serious offshore boat should have contact with a marine or wilderness medicine expert. At least one person onboard should have a minimum of training, and your expert should prescribe you the basic medications to keep onboard that you might need to stabilize an emergency. And you need to have a PLAN. In the case of a serious health emergency or trauma, who are you going to call? What are you going to do? Not having a plan is the equivalent of just throwing up your hands and saying, "You''re gonna die! So sorry!"

Finally, these days there is simply no excuse for having "zero connection to the outside world". Not having basic emergancy communications is putting a very limited value on your and your crew's health and safety. I certainly would never be on a boat crossing an ocean that had zero communications once out of sight of land. If you want to be a crazy historical re-enactor I guess you might do that, but no rational person would.