I kinda stopped caring about it and over time, on electric at least, it sorta just came along. I think there was just general strength development over time in the index finger as well as learning how to position the bar optimally for your particular finger and the shape of your guitar's fretboard.

That being said, I'm not sure it's worth stressing over. Unless the kind of things you want to play are all about that kind of sound, bar chords are somewhat overrated IMO. There are other ways to play the F harmony without stressing about that bar and other ways to play chords beyond the E-shape bar chord ... all of which are pretty valuable to learn and might, depending on what you want to play, be a better investment of your time.

Just in case you don't know what I mean by other ways to play F ... the most direct would be to drop the low F on the low E string but keep all of the other notes. IE, fret like so: "X33211" with the "11" on the B and high-E strings being a mini bar with your index. You can simplify this even further by dropping the note on the A string and just having "XX3211". A nice perk of playing it this way is that the Maj7 is easily available by lifting the index off of the high-E string to play it open. You can also add your pinky on the 3rd fret on the high-E to hit the Maj9, a very nice chord.

Going beyond that, you can take the open C chord and slide it up the fret board, and don't play the low-E and put a mini bar over the three high strings where the G and high-E strings would be open on the C chord, and you've got a different way of playing major chords. Here again you can not play the note on the A string and just play the four high strings, or not play the high-E string and just play the middle four strings.