Hmm, yeah, I didn’t know yeast messes up autolysis. I add everything in the evening and put it in the fridge, maybe it still works since the yeast takes a while to get going in the fridge. I also use cold water instead of lukewarm to slow it down even more, the goal is a slow fermentation overnight to get flavour and develop the gluten, while making sure the yeast still has enough “energy” for a rise in the morning. I guess you could also let the flour and water sit for a while before adding the yeast and salt and putting it in the fridge to make sure it really autolyses.
For high hydration, using high protein flour and letting the dough sit for a while before trying to work it really helps in my experience. Also, wetting your hands before touching the dough, but I imagine you’re already doing that.
Looks like Fomitopsis betulina to me, probably started fruiting when the tree had already fallen