2 tries at pan de cristal failed.

As for the soft crust - here are a few hints and ideas.
- higher hydration for the dough (I know it's hard)
- lower fermentation/rise time
- keep dough moist / don't let it dry
Basically you don't want the dough to develop any "skin" at all. Buy yeast and try to make rolls. Use a lot of yeast, so dough will rise fast. Around 65% hydration is enough for that experiment. Keep the dough moist all the time. Use plastic bags to prevent air to get on the dough.
When baking, use steam a lot until the rolls won't rise anymore. Then open oven to release steam. 10s is NOT enough. Better go for 1 min or so. After baking let rolls cool until they are around 40°C, then put in plastic bag or cover etc. The remaining water in the crumb will soften the crust.
Good luck!