If you are going to be inverted on the ceiling holds I would never trust lag bolts or any other vertically screwed anchor. You risk them pulling straight out of the wood and falling on your head/neck.

The only truly safe ceiling anchors are thru-bolted through the joists horizontally so you rely on the shear strength of the anchor bolt. Just make sure its anchored in the upper 1/3 of the joist so there is plenty of wood below the bolt.

If you must do some sort of vertical fastener then Climbing gym setups are the ideal solution for thru-bolting. I think they use at least 3/4" plywood with rear metal anchors that bolts screw into. They are Best for a angled or vertical walls because you are using the shear strength of the bolt. But because they have a metal backing they are probably also ok for ceiling mounts. You could try to get extra large metal backings with a large washer to mitigate any potential pull through risk.

Attach the plywood to the joists with carriage bolts (lots of them). That will distribute the load across the whole plywood and not just a single lag like the monkey bars in the link you posted.

You'll have to self tap all the screw holes for the metal anchors on the back side tho. Search custom rock climbing walls for lots of tutorials.

Also you may want to double check your homeowners insurance. They may not cover damage to the house structure if you happen to deform or break anything because of your use case.

Not trying to be a downer but a person I knew fell from aerial equipment that failed and ended up partially paralyzed.