Something fundamental is missing Dr. Watson, a mystery is afoot.
Between Special relativity and Quantum mechanics there is something missing that could modify both systems toward more coherency. If found, it would be a game changer but probably not the theory of everything.

That one thing may be as simple as negative mass. An atom has a negative particle, a neutron and a positive particle. Negative mass has some people proposing it may even be the dark matter blob like fluid and has the potential for acting like dark energy as well.

Richard Feynman proposed that time also goes backward so negative mass may not be the only one thing we got wrong. I don't know one Maxwell equation from another and lack certain fundamentals but the properties of negative mass are amazing and unintuitive. Push on it and it pushes back. Pull it and it acclerates away.

Where did negative mass come from? The annihilation of a billion anti matter atoms and a billion postive matter atoms supposedly left one postive mass atom out of the fray to go its merry way. Thats a helluva lot of annihilated residue that didn't all zip away as pure energy. The left over positive mass is everything we are and see in the universe.

The great annihilation event may have also become the invisible negative mass fluid we are calling dark matter and the missing mass in the universe.

We have room for mass, massless particles so why not negative mass?