I don’t see this as a place to slow down, but to play it quieter (as indicated in the score) and with a sense of quiet urgency. I see the bass triplets in this section to be a foreshadowing of the bass triplets in the recap, I’m not sure from your post if you consider, or not, this entire section to be problematic. If you do, don’t forget that the LH in bar 38 is marked staccato I would recommend that you listen to as many professional recordings of this section as you can find
When I play this, I think the change is rather abrupt, and this annoys me, since I think it doesn't fit so well with the tranquility and tenderness of the piece as a whole. Not that I have any issue with the triplets per se, I think the part from bar 36 to the end is beautiful, it's the transition that bothers me.