The problem with your kind of thinking about the age of the earth and universe is, there is all kinds of evidence that the universe is much shorter. Some of the evidence points at 10,000 years. Since you can do Internet searches that show this, and since you can get deeper by studying the young-earth evidence with those who explain it, believing in a old-universe view is a choice... not reality of an old-universe.
In other words, whatever looks good, and however you want to apply the evidence, is like making a choice to believe whatever you want.
The only way to know how old the universe is, is to believe the witnesses who were there, and recorded their witnessing.
The first two chapters of the Bible were witness records copied by Moses from text in Egyptian libraries about 3,500 years ago. These texts probably have crumbled away with age long ago. But they might still be hidden in some lost Egytian library somewhere... hidden under the desert sands of Egypt.
You can't apply today's evidence without knowing the past parameters that the evidence needs to be applied by. Maybe they are applying the evidence in a wrong way. We won't know until we have witnesses or a time viewer/machine.
You have such a machine, its called a telescope. Yes, indeed, whatever you see in the sky is already very. very old, much older than 10 thousand years. And the more you "zoom" in, the farther in the past you pry (not just further away).
Time and Space is relative. You think you could make things simple for you to understand it, but the universe does not care, it simply is.
Time and space are relative. But why does anyone think that the relativeness hasn't necessarily changed over the ages?
For example, you have some cookies. Obviously they were baked. How do you know if they were baked in an electric oven, a gas oven, or in a closed frying pan on on top of the range? You might be able to chemically test some samples. But if they are out of reach, and you test with a spectrometer, how do you know that you aren't missing some variables in the whole test method?
All we are seeing is light through the telescope. We can understand that light from near objects (in out solar system) has been operated upon by the same physics that we use right here on Earth. But what about the light that came over distances that might be millions of light years? How do we know that the physics of the past wasn't different, and only makes the light appear to be millions of light years away.
I'll bet that there are plenty of astrophysysicists who are mathematicians who could calculate a very different distance by calculating a gradual change in math and physics into it. But why do this when it is so much easier to use all kinds of constants that we don't for-a-fact know existed more than a million years ago?
In Big bang theory, we aren't missing variables. BBT says 3 things:
1. Here's the way BB was;
2. We used math, physics, astronomy, etc., to extrapolate backwards to get BB;
3. BB was different than what we have today.
What was different about BB? Well, the stars, the operations of forces, mechanics, math, physics, time. We don't have any frame of reference to tell what the differences were, or when they arose, or if they somehow acted with something like punctuated-equilibrium, or if they entirely smooth changes.
Essentially, BBT has destroyed the BB it created. The best we have is records of the ancient peoples of the world in their pottery, writings, and "sculptures." We don't know how far back (years) beyond these we can go with the same math and physics that we use today. Even now, science is showing with Gobekli Tepe and other places that our calculations of time are way off base.