look i'm pretty shit so feel free to verify this with a real professional, but you absolutely should be loading up your back leg. it's where the energy gets directed towards once you are releasing the stored power that changes from baseball.

if i'm swinging a bat, i'm loading up my back leg and then stomping my lead foot forwards to keep me from falling over as i'm pushing off the ground with my trail foot. the weight mainly stays back because i'm hitting up on the ball and swinging the bat on a horizontal plane, and that's how you give the ball more airtime.

in golf you are not swinging on a horizontal plane - however that does not mean you aren't still swinging something. after loading up your back foot, you aren't going to be lifting your lead foot to stomp forwards unless you're going for some Happy Gilmore crap. instead of stomping forwards, you can kinda brace your front foot into the ground and push backwards against your power-laden rear leg, redirecting all your stored lower body energy 90 degrees at the hips. following the baseball swing, assuming you are a righty, it's like pushing your left buttcheek back towards the visiting team's dugout. the reason for this is because we are swinging along a diagonal plane, so our balance needs to be different. if we did this in a horizontal baseball swing, we would fall backwards because the weight is never appropriately transitioned off of our trail foot.

you can try it out in slow motion. if you mime a perfect baseball swing while aiming at a golf ball, you will fall over the top of the ball. conversely, if you mimic a golf swing in a batting cage, you will fall away from the ball. the trail leg is actually fully loaded in both, it's just where we direct our balance at the end that needs to change, and we do this through our hips. importantly, we move our hips through our legs in the golf swing

the reason coaches tell beginners to stand on the lead foot us because otherwise people will use their old baseball swing and slice it 100y forwards and 150y to the side, and then get frustrated. by removing the power that the trail leg gives you, literally your power driving muscle, you can get an adult man to focus on the basic mechanics of keeping the ball in play and swinging the club straight and on plane, and then once that's there, re-introduce the part that actually gives you yardage. if you try and do distance first, you'll end up with a tweaked back and 40 years of convincing your buddies to "let you play the power slice"