Rather than repeat the previous thread, how about reviving a thought by Dirac. At one time he postulated that antimatter is a "hole" in an unseen sea of normal matter with negative energy.
With the current idea that there is "dark matter" everywhere, undetectable by us at this point, what if antimatter is basically a hole created in the "dark matter" that gets created by energy being absorbed by the dark matter, making a "new" visible piece of normal matter and its visible "antimatter" counterpart being the "hole"? Then, annihilation is just the normal matter releasing its energy and falling into that hole.
If so, then no need to explain why there was not the same amount of antimatter and normal matter created by the Big Bang, which would then have totally annihilated both into nothing but energy, with none of either left over. That clearly did not happen. With this negative energy mass as the "dark matter" we would just have about 5 times as much matter with negative energy as we have with positive energy, to get the total gravitational mass to fit observations.
Not the most popular concept, but if you believe in "dark matter", then there is
something all around us.
There is more than one way to represent "negative energy" with mathematics. One way is "negative mass". I don't know what to say about how gravity would work with "negative mass". Intuitively, it seems like it would be repulsive instead of attractive, which would not work as "dark matter". (Might has some interesting conceptual implications for dark energy, though.)
Another way is to have positive mass but "imaginary velocity", where the square root of negative 1 is represented by "i", so that the square of the velocity is negative. It sounds strange, but there are already successful mathematical treatments of real phenomena that use "i" in "complex numbers" that have a "real part" and an "imaginary part", so written x + yi.
This link explains the math:
https://www.quantamagazine.org/the-imaginary-numbers-at-the-edge-of-reality-20181025/ .
And this link explains real physical phenomena that are described in engineering calculations with complex numbers:
https://issuu.com/harrowhongkong/docs/final_scientific_harrovian_issue_vi-i/s/11488755