No worries about taking time, I'm on social media less and less myself these days. I think the biggest problem with the way you're looking at the TRPF is using microeconomics to describe a macroeconomic pressure. Marxist analysis stresses the interconnectedness of economics, and trying to view 2 companies while obfuscating the rest of the economy is going to run into false assumptions about a general pressure that applies to economies at scale.

In the instance of R2 and R1, the decline in costs from the input of R1's price to R2 applies to the rest of the chair manuracturers. If company 2 doesn't also lower their prices as their cost of input has lowered to match other chair companies, then they will run into fewer total sales. Competition places a negative pressure on Surplus, and increasing productivity of machinery increases Constant Capital in relation to Variable Capital, so the biggest source to counteract the Rate of Profit's decline is by lowering V or stagnating it with respect to productivity, which is what we are seeing now more than anything else.

As for OCC, think of it in this manner: if machinery costs less for better productivity, then it will be employed more. Economies of scale work precisely because of this grand increase in OCC, which is why equivalent goods cost so little today in comparison to 50 years ago. Selling more widgets for a lower rate of profit per widget but greater total profits is the bread and butter of commodity production, and industrialization. If a worker at the widget factory produces 100 widgets with machine A, and 1000 widgets with machine B, then the OCC is rising. Automation increases OCC. Here's Marx in Capital:

However much the use of machinery may increase the surplus labour at the expense of the necessary labour by heightening the productiveness of labour it is clear that it attains this result, only by diminishing the number of workmen employed by a given amount of capital. It converts what was formerly variable capital, invested in labour power, into machinery which, being constant capital, does not produce surplus value.....

[Emphasis mine.]

I really don't know what it is exactly that you're taking issue with. If you agree with Marx's Law of Value at its base, then the TRPF follows from it mathematically as a general downward pressure, not as an ironclad linear relationship. If you don't agree with Marx's Law of Value, then the TRPF isn't worth fighting against, there are other more standard attacks on it. Do you consider yourself a Marxist? That might help me understand where you're coming from a bit more.