If you're halving trouble with the half barre, you can try a full barre. Sometimes that is easier. Depending on the song, you might also be able to get away with 3210 instead of 3211, which would be a Bb major seventh chord. Or even 3010 which is Bb major ninth.
Keep at it!
No matter how frustrating it may seem, do not go down the road of substituting this for that - just knuckle down and learn it.
The advice above about action - the height of the strings above the fretboard - is certainly part of it, but there is another piece that is often overlooked, especially with those new to stringed instruments.
As much as you can, try to keep the fretboard perpendicular to the ground. Often people just starting to play have the top of the fretboard "leaned back" so that they can see their fingers. This makes the left wrist bend much more than it needs to, causing it to be more difficult to fret the notes and will also cause fatigue much faster.
I know, you say you can't see your hand! BUT you are supposed to be looking at your music!
Anyway, try to lean your head over if you need to look and keep that fretboard vertical.
Also, many times you press much harder than you really need to when you are starting out.
Relax.
Yes, it feels weird.
Yes, it gets easier.
Use the tips of your fingers to fret the notes, not the pads.
Get that nice arc in your fingers to go around the non-fretted notes. You will find that is easier when you don't have your wrist bent over because you are holding your fretboard vertical now.
Hope that helps, and keep at it! You can do it!
I'm sorry I don't understand. Music theory that is.
Then don't worry about the theory. Just play the chords and if it sounds good, play it again. .
As much as you can, try to keep the fretboard perpendicular to the ground. Often people just starting to play have the top of the fretboard "leaned back" so that they can see their fingers. This makes the left wrist bend much more than it needs to, causing it to be more difficult to fret the notes and will also cause fatigue much faster.