The problem, as you've found, is that most Ti seatposts are designed with lightness in mind and have lightweight saddle mounting systems which can have problems with heavier riders. I haven't seen them all but I would recommend something sturdier for your weight such as this style with two bolts anchoring everything in place and a beefy mount with a slightly larger clamp area for the saddle rails to keep them from bending.
https://www.ebay.com/p/1544415147?ii...CABEgLLQPD_BwE Lighter is always good but sometimes us larger types have to sacrifice a little weight for durability.