"Science" is in this general sense excellent in many different scientific departments and specialeties, but regarding the modern scientific approach to the concept of "Cosmology", it is a question of whether this science have lost the ability of Natural Philosophical thinking compared to the ancient method which lead to the
Greek philosopher´s discovery of the atom.
"Calculus" is also fine art, but when the perceptions and hypothesis are wrong, it lead the modern cosmology far astray in all kinds of pure speculations, also because of not acting accordingly to the strict scientific methods of changing hypothesis when directly contradicted by factual observations.
When the Newtonian perception and theory of celestial planetary motions was contradicted by the observed
galactic rotation curve, cosmological scientists should have abandoned this perception and theory and revised the entire idea of "gravity" in order to follow the scientific method, but they didn´t.
Instead they invented "dark matter" and "black holes" in order to patch and hold onto their contradicted theory and calculus. They added some "metaphysical matters" which an ancient natural philosopher NEVER would have done. They would have looked everywhere in order to find natural patterns which could illustrate the orbital observed pattern in galaxies - and they would have found such a pattern in the motions of hurricanes and simple weather systems and based their theories on natural phenomenons and not on something "dark this or that" which wasn´t observed.
Modern cosmological science needs Natural Philosophy very soon before it ends up in the speculative nothingness and pure science fiction.
That because you are assuming and confusing theoretical science with empirical/experimental natural science.
Theoretical science are not actual science, because they are untested, relying mostly on logic and mathematics, not evidences used in experimental science, following the falsification and scientific method.
Theoretical science are basically hypotheses, that are currently untestable. The only thing saving any theoretical models are their maths (proofs), but maths are not evidences, and they are not inerrant.
What you called speculation, is under the theoretical physics umbrella.
Some fields in theoretical physics do become experimental/empirical science. General Relativity, for instance, expanded/extended our knowledge on gravity, because the Newtonian gravity isn’t enough when it come to describing distant galaxies and other astronomical bodies.
A lot areas in astrophysics and cosmology are still unknown, but we have learned far more in the last two centuries than in Galileo’s and Newton’s days.
Cosmology is work in progress. You cannot expect science to know everything.
Philosophies cannot help anyone with cosmology. Philosophies are no better than religions when it comes to cosmology, because different factions in different philosophies, philosophers are constantly fighting each other over superiority against each other, doing know works.
And metaphysics is the worse of lot. It’s all talk but no work.
Metaphysics is like the very popular geocentric model of planetary motion, which ruled for millennia, since the Sumerian/Babylonian astronomy, but it was Ptolemy who made geocentric popular...but it was wrong.
Metaphysics is popular, but overrated just like the geocentric believers or the Flat Earth believers.