Joining the ends of two balls of yarn

Dear users, dear authors,
how do you join two balls of yarn at their ends so that they don’t come apart again?

I usually use the Frankfurt knot. You can’t see it, and so far it hasn’t come undone.

If I don’t tie it that way, I weave in the yarn ends.

I do that too. I didn’t know that’s what it’s called—I had to look it up first. I found it on YouTube as the “magic knot.”
It works great.

I usually knit 3 or 4 stitches with both strands and then sew the ends together.
If possible, I do this at the edge of the knitted piece. It’s always worked for me so far.

I use the Frankfurt knot when I knit in the round, but I still weave in the ends 😇 What I do most often when knitting knit stitches is use the Fair Isle technique and “weave” the threads into the fabric for a few stitches. So I knit across about 20 stitches with both threads... This only works for me when knitting knit stitches; on a purl row, I let the old and new threads hang for a moment and then “weave” them into the row above....