You sure can slow-pitch in shallow water, just need to downsize. I SPJ sea trout from my dock in 6’ to 12’ of water, depending on the tide. Now I’m not using 100g jigs of course! My go to jigs are the BlueBlue sea-ride minis from 3g to 12g. Don’t know of any SPJ rod that than work jigs that small so it took some looking but I found a Egi rod that is perfect. It’s a Squid Wicked Game rod rated for squid jigs up to 25g. Matched it with a Shimano sustain Ci4 1000. It may not be a vast water column to travel but a super slow slight lift, pause, then another super slow lift, drop and repeat is usually all it takes. I know it’s not true SPJing but it’s as close as you’re going to get in that little bit of water. But, man is it fun when you’ve hook up.