This video explains what may be the hardest concept to grasp when dealing with the Trinity doctrine, the use of words. Of course it does not deal with other elements of this doctrine, just the use of words.
Yes, the video is an oversimplification, but it is to show that the word "category" is typically masked by the use of many other intellectual-sounding words such as subsistence, spiration, emanation, homouseas, 3 persons in 1 being that is not a person, man but not a man, consubstantial, unbegotten-begotten, filiation, procession, perichoresis, triune, interpenetration, bla bla bla, all to mask the fact that it is 3 Gods in one God category, unless you think the Trinity is also God, in which case you have 4 Gods.

This video is my own creation, not sponsored in any way by the https://www.unitarianchristianalliance.org

https://www.youtube.com/unitarianchristianalliance