TOAA chose Thanos because only Thanos was able to contain THOTI's power.
While Thanos was manipulated into acquiring THOTI,
Thanos still had to work for said aquisition,
and Thanos was searching for THOTI since the Infinity Abyss arc.
That aside,
it was Thanos' decision (not TOAA) to either re-create or leave Marvel as a void.
(from an in-comic point of view that is)
(from our real world point of view though)
There is nothing anyone/thing can do in Marvel without TOAA making it so,
since TOAA governs the actions and thoughts of everything Marvel on panel.