Welcome to the world of handgun hunting and to this site. You have a fine rig for deer assuming you know your limits and pick your shot opportunities well. The red dot is s good choice for 50 -75 yards on deer. Again it depends on your skill level to hold and place the shot in the heart / lung area. I suggest broadside or quartering away as the preferred shot. I suggest 158 to 180 grain ammo.
The only ?secret? I can add is to practice, practice, practice. I would suggest buying a .22 rimfire or a quality air pistol and shooting regularly. Good luck and enjoy.
"Therefore go and make disciples of all nations,... "
Handgun hunter since 1979 - haven't used a rifle since!
HHI member #992, NRA, SCI.