I deeply appreciate your succinct and forthright explanation of the Standard Model in layman's terms. I hope your presentation achieves all your goals for it. I have great reticence in sharing my rude grasp of physics as an unlearned layman, but I seem to understand gravity differently than I have heard expressed by anyone I have read more extensively. From Einstein's description of gravity as the warping of spacetime I note that gravity is not a force anymore than volume is a force. Dropping a stone into a pond results in pressure on the water to move to accept the volume displaced by the stone, and similarly mass affecting spacetime produces warping as a result, and neither volume nor gravity are forces per se, although producing affects involving forces.
Since gravity affects spacetime, which is neither space nor time, I understand it's affects to extend across the full breadth of that medium, and it seems to me that dark matter is proposed to account for the affects of matter at other times that is not apparent presently in the visible space.
This does not accord with the standard model as I understand it, and I am incompetent to even contemplate treating this understanding mathematically. Frankly I can count past twenty if I am without pants, so am curious if my understanding has any basis in such facts as you believe demonstrable, or if it is contradicted.