Really ..."Speculative, unproven?"..you admit we seen light bend..it a way predicted..what other force to you proposed?..have we Observed your proposal unknown force acting on any thing else?..or to content gravity done not exist
You seem to be contenting a force we we observe acting on objects ...
That we call "gravity"
which you also agree that we don't really understand how it works...
is not the same force we see acting on light...
and you propose a 2nt unknown mystery force acting on light
yet don't see observe this 2nt unknown mystery force acting on anything else.
What we call "gravity" is observed..acting on matter in a predictable manner...
and we observed light being acted on in what appears to be the same predictable way gravity acts on matter
Buy you say it not gravity acting on light with a contradictory statement
you say it can't be gravity cause gravity can't act on light because light has no mass...then go back to say we don't understand how gravity works
so your statement ..gravity can't act on things without mass ..and we do not nderstand gravity is contradictor
...also add in do we completely understand how light works in that acts like a both a wave and a particle
.. so we're stuck with just observing a predictable behavior
that light and matter both react to something in the same way...that we call gravity
it’s called refraction and doesn’t rely on any voodoo mysticism to explain it, just plain old classical physics
that’s why Einstein rings are blue... this is a refraction effect