Any way to replace exterior handle?

I'm afraid there isn't any easy shortcut to the repair videos. The door handles are made so that you have to take the door apart to replace them; if they were easy to replace from the outside, there'd be nothing to stop you from breaking into the car by removing the handle.

It's hard to say with 100% confidence without seeing pictures or knowing exactly how your handle is broken, but I can tell you right now that there are very few ways to join those broken parts together so they will hold against the stress of activating the mechanism and pulling the door open, and nothing you've listed will do that job. Under some circumstances you might be able to get by with some epoxy-based glue such as JB Weld, but as far as repair goes, welding is the only thing that has a reasonable chance of success, but that still depends on the kind of metal the handle is made of.

So my advice is to bite the bullet and resign yourself to either not using the door or going through the whole "breakdown video" procedure. Here's one for the rear door(s); it should be close to what you would have to do on the front doors too.

How to Replace Exterior Door Handle 02-06 Nissan Altima - YouTube