If I am wrong about anything here, please tell me.
I don't think anything you have said is wrong. Actually, I think you may have highlighted something unintentionally, being that if there is a correlation between the supply of Bitcoin and the supply of gold nearly being exactly a factor of 10. Very interesting!
As for price predictions, you have a good argument with gold against BTC. The only missing component that might limit the highlighted potential of up to 600k USD (at current gold prices) is the loss of market share from gold because of Bitcoin. At the same time, gold may/should increase in price as fiat money continues to fall.
At the point that fiat money becomes worthless, then is a good time to revisit these calculations to find the difference where Bitcoin would become on par with gold...or, where Bitcoin would start to take the market share of gold due to fiat money becoming irrelevant and
gold/btc being the new pair to be watched. It might seem unrealistic to think about this now, I believe over the next decade this will be worth revisiting though.
Long term it probably makes sense to think about Bitcoin's price appreciation in terms of BTC/GOLD rather than BTC/USD just because yeah the USD will every year get less valuable and that will compound over time. Like 50 years from now Bitcoin will likely be worth tens of millions of dollars partially due to growth but partially due to loss in value of USD.
Let's say USD's average inflation for the next 50 years is 3%, because it seems unlikely they'll get it back under 2% long term considering the fiscal mess the US govt has been in the past 20 years and that isn't going to change. 50 years of 3% inflation means the dollar will only be worth 21.8 cents of what it is today. So roughly means everything that mains value or cost over time will be 5 times as many dollars.
Now if we project Bitcoin's natural slowing rate of growth in value, and say the average growth rate in pure value over time will only be 10%/year over the next 50 years starting with this year at the price of $17k, that puts Bitcoin at just about $2 million in today's dollars, then add in the 5x factor to account for inflation and that prices bitcoin at somewhere around $10 million in 50 years. Which is just getting kinda of absurd because the dollar won't be worth much at that point, I mean at that point a good hourly wage earner might be making $100/hr.
But if Gold can roughly keep its value, and therefore is around $10,000/ounce (because of inflation's 5x) we can still compare Bitcoin to Gold to get a much better idea of its appreciation against something that is at least somewhat more stable in value. In this case in 50 years Bitcoin would have gone from roughly being worth 10 ounces of Gold to start 2023 to being worth 200 ounces of Gold in 50 years, in this example. That way its easier to see that Bitcoin would have roughly gone up by 20x as a store of value, rather than the >500x against the USD which isn't really helpful.