Does Deep Thought Lead to God? Here's a Shallow Answer

[Mudhammam]

I have no idea what that means. Case in point. Foundational reality, sure, but I have no idea what "preserves being throughout change" even means.

Here's another case in point. Someone please parse this Tillich quote into English:

..It is the expression of the experience of being over against non-being. Therefore, it can be described as the power of being which resists non-being. For this reason, the medieval philosophers called being the basic transcendentale, beyond the universal and the particular...
The same word, the emptiest of all concepts when taken as an abstraction, becomes the most meaningful of all concepts when it is understood as the power of being in everything that has being.

Utter gobbledygook. The power of being in everything that has being?

I take that to mean the potential for being from non-being is a power (or principle) of being that exists in everything that has being (the sum and parts of the material Universe), and exists prior to the actuation of its being.

Without a fuller context of Tillich's theology, since I have never read him and only share a marginal interest in doing so, I have no idea what he might possibly mean in the other quotes you offered.