A few years back to get my lowered truck through an arched 7ft garage door I chopped down the stock antenna 4-5".
It was a pretty straightforward procedure.. pull off the top ball, chop the mast down a bit (careful with the spiral wire wound around).
I had to bevel the tip to fit back in the ball and used friction plus green loctite retainer to glue it back together.
It's cheap enough to buy a new shorter one, but since I had all the stuff on-hand to shorten mine a penny-saved... I also liked
that I could get a custom length that was just slightly taller than the roofline as a clearance indicator.
Pretty much any antenna change will affect your reception, keep that in mind. Since radio is a range of frequencies and antennas
are aiming for a multiple of the size of the wave, some stations will likely improve with a small change, and some will likely degrade.
Of course change it enough and they're all out of range. Hopefully the stations you like are in the better group, not the worse.
On the '19 so far I found that removing my antenna entirely has worked out great but I don't listen to the radio lol.