Interesting topic and I have thought similar thoughts as you. We do know from scripture that the Holy Spirit is mentioned in context of certain tasks / functions that it fulfills. Also Jesus many times distinguishes the Son from the Father. So Father, Son and Holy Spirit are separate persons and apparently have distinct roles. However the details of how the trinity works is beyond any of us. All we have is the scripture.
I agree. Scripture gives us much to ponder and be in awe of. Even with the personal relationship He established by walking among us, we will not comprehend everything until He brings us home - and even then some may remain beyond us. God Bless.