I don't know where you got those notions from, but since a lot of people recycle copper I don't think we're going to run out of it, much less in six years. Helium I have no idea about, but that'd suck for all the kids' birthday parties that depend on balloons. AFAIK there's no substitute for helium.
According to USGS data, since 1950 there has always been, on average, 40 years of copper reserves and over 200 years of resources left.
That is from
https://internationalcopper.org/sustainable-copper/about-copper/cu-demand-long-term-availability/Helium however is of major concern: With production facilities coming online in Qatar and Indonesia we will be good well past 2030 but - we
are running short per
https://www.iflscience.com/is-planet-earth-running-out-of-helium-70630 thankfully many critical uses of it are implementing conservation through better insulation and temperature shielding methods & for semiconductor and welding processes are minimizing usage as much as possible but nonetheless this valuable and irreplaceable gas IS running out.
Back on topic.... There are only about 20 years of known silver reserves left per
https://www.physicalgold.com/insights/how-much-silver-is-there-in-the-world/ According to estimates from industry sources, if silver mining were to continue at current annual rates, there are roughly 20 years’ worth of identified and undiscovered global silver reserves remaining. However, that assumption is based on silver extraction levels remaining constant and no new reserve discoveries.
The methodology that you use is flawed. For metals such as gold and silver, low grade ore is present in earth's crust in relative abundance. As of now, it doesn't make any economic sense to extract metals from this low grade ore because of two things - technology is not very advanced and cost of extraction is more than the market cost of the metal. And in near future, both these aspects can change. And this will cause significant changes when we calculate the total reserves for precious metals such as gold or platinum.