Designing a 3'x8' platform to hang from my basement ceiling struts; Please provide feedback (pictures in post)

Design:

https://i.ibb.co/rGsryFsJ/Screenshot-2026-03-02-110138.png

https://i.ibb.co/PvhMhfmN/Screenshot-2026-03-02-110155.png

https://i.ibb.co/HfqPkbWP/Screenshot-2026-03-02-110213.png

https://i.ibb.co/WW25fyXS/Screenshot-2026-03-02-110254.png

https://i.ibb.co/d0t3M82F/Screenshot-2026-03-02-110230.png

Gonna use some 2x4 and some 2 1/2" screws to fasten it all together. It will be up against a basement wall (cinderblock). Struts are 2"x8" spaced at 16" apart.

3'x8' plywood is 3/4" thicc

I would like it to be strong enough to hold at least 500 lbs as it will be holding drums, drum hardware, 3D printer filament, and all sorts of heavy shit. I also have a daughter/wife and 2 cats that may walk underneath of it from time to time so structural integrity is an absolute must; no exception and no shortcuts.

Was thinking about using lag-bolts to fasten the 2x4 to the 2x8 struts for more strength but not sure if its necessary. I feel comfortable with this design, i just wanted to reach out to see if anyone who knows more than me could provide some constructive feedback.

I'm pretty handy and all that but i'm not a structural engineer and I do DIY stuff as a hobby and to save money so i'm not a professional.

i'm responsive so if you want any other details lmk. design done in Fusion360

Thanks in advance yall, cheers