Try the DeSoto Power Tri-Shorts. They’re made with a heavier weight of lycra and support better than anything else I’ve tried PLUS they’ve got pockets on the side for gels/salt tablets/etc.
Shifting gears, don’t underestimate your transitions. I did the complete wardrobe change at my first IM and my T1 & T2 times combined were over 15 minutes (plus sitting in the changing tent to put on your running gear after getting off a 5 or 6 hr bike ride is just begging for something to cramp) compared to my 2nd where I wore a DeSoto Power Tri-Suit and cut my transition time in half. That’s like getting 8 minutes for free. FTR, I have no affiliation with DeSoto whatsoever but I used to work in a running store and have tried clothes from almost every company that makes tri gear and DeSoto has consistently been at the top.