This might sound simplistic, but what about getting him into nature, playing some sports, and making organic connections between the activities and experiments he'd like to conduct?
My DS6, for instance, is interested in parkour gymnastics. It involves a lot of free running and environmental movement, which has been a bridge for him into physics. He'll try out a new move, then sit back and assess how the result aligns with different rules he knows (he's quite into Newtonian physics now). When he sees results from his knowledge, it fuels a strong desire to learn more.
Ditto water sports--it's a natural entry point into fluid dynamics. He went on a tangent yesterday discussing how to react if your car is submerged in water, and had put together a surprisingly elegant discussion of differential pressure.
Another idea--try out a maker space, or make your own at home. Any activity that involves the design process, material sourcing, and planning is rich in teaching both the science substantives and the executive function required to support inquiry.
And...BOOKS! Read together, read separately, discuss interesting/exciting things you've learned. Make a family seminar where you get to present neat concepts and new ideas.
I'm not against virtual learning, but it sounds like you've got those bases covered already and need some branching out.
