Auto creat slab between beams & columns

Try RFL FLOOR

i would love but i dont see any component on that level in your sample rvt, but will guess its almost the same, now we have given some hint both from Christian and me now its up to you, play around with it…but as you see many things can go wrong, it can be bad modlled or something else…and the community isnt a place where we do the project for you…good luck

Here is a workaround with Package Ampersand at the output of the isolated top surface to recover the internal closed loops

Sincerely
christian.stan