Of course, I might be misunderstanding your particular issue, but when I've come across this type of problem in the past with relatively inexperienced guitarists, I've suggested that they try fretting the notes with their nose.
This sounds stupid, but what it usually illustrates is that you don't need an awful lot of pressure to fret a note.
So finger strength is not an issue - unless you want to crack walnuts as a party trick as a side show.
I'm very experienced so I hardly need any pressure at all - this means I can
slide double-stops or chords without difficulty. But I can't crack walnuts. It's not so much finger strength as control - and that comes with practice. It helps if you can relax too. Try some relaxation exercises before you play and see if that makes your playing smoother.
I guess the trick is to use control to hold the chord shape, not finger strength to squeeze the string into the fretboard. If you played the tune with your nose you would use the minimum pressure possible.
I always say that it helps to turn the amp up to 10, too. Of course, it doesn't help at all, but it makes it much more fun.