Look at some of the Fager snaffles. They have the Lilly snaffle in titanium, available in fixed rings and loose rings. They designed the mouthpiece of this bit so that the single joint in the middle will not hit the horse’s palate, https://fagerbitsusa.com/titanium-bits/products/fager-lilly-fss-titanium-loose-ring.
The Fager people make a LOT of different types of snaffles, different mouthpieces, different side pieces, different metals (titanium or sweet iron) in regular versions and tongue relief versions. The problems are selecting the right one (you can message for advice) and also the price (today it is US $165.00 for a lot of their snaffle bits).