I don't even see why it's so important to believe in a trinity or not to believe.
The Father, the Son and the Holy Spirit are all spirits, literally air, wind, breath.
We can't see it, even though it's all around us, to me it's like arguing whether the wind is square, round, oval etc.
Humans try way too hard to visualise everything, but we can't, many times we just need to accept that not everything is seeable, it's not matter. Our brains seem to struggle with that.
Spirits are all around us, they can shape shift, enter and leave physical bodies, (human, snake, donkey, pig), walk through walls and doors, move physical objects in their spirit state etc etc.
I think they could probably do the same with each other whenever they choose to, and undo it when needed.
I doubt very much that anyone's salvation depends on whether you believe in a trinity or not.