I have the same problem as Jax above. Would really appreciate a solution or insight to help a anxious child who can’t wait to get back on Java
This is happening in my Bedrock Realm too!
I also experienced this. My basement in one of my realm houses is very well lit, but one time I went down only to find a creeper there.
Same issue. I have a pbr resource pack in my global resources. Make new world in preview, activate experimental features, activate pbr resource pack (tried both as global resource and specifically just for world), and just like you the "deferred technical preview" option is greyed out.