Hey @OneSeventeen - Believe it or not I started typing a response last night, but got so engrossed in it I didn’t finish until just a moment ago.
Suffice to say, you have gotten some great answers as to how you should go about accomplishing your request. @jamesvavra made the most important point already about moving your L3 subnet gateway ip’s to the L3 switch and turning up a switch-sonicwall route to handle traffic to preserve your client config. @MagnaVis gave some great additional context as well.
It was @BenCarlson who linked to an IP spreadsheet that really got my excited though. Proper subnet planning and how that intersects with route layout is something most people don’t recognize the importance of until far after it is to late. That subject is essentially what I am addressing in my post Which you can find here.
Regardless. Great question.