Hi
Even though I cannot comment on this (results and apdl snippet - perhaps some other forum users that use this element can), I would like to suggest the current elements (solid187) and using the Menetrey-Wilam or DP concrete models, for modelling this type of structure and failure.
(Solid65 is an old legacy which is mesh sensitive and can produce different results for different meshes)
There are many posts in this forum on using this approach and I have written it in an old post (it does not exist anymore as it was in the old forum) a small tutorial on how to do a punching shear example.
Also in help we can find some examples tech demo 49 and 52
49.1. Introduction (ansys.com)
For reinforcement use the reinforcement element/option in workbench.
https://forum.ansys.com/forums/topic/reinforced-concrete-with-shear-reinforcement/
Hope this helps and all the best
Erik