you have many question, i try to answer the 1st question.

on market too many alt coin
how can we control the shit coin?

• what we can do as investor is do research on coin legitimacy, seek advise on others, determine the future of the coin, if you like it, invest, else just leave it. Thing is , investment always a risk. you never know for sure the coin is a shit coin, scam coin or hidden gem or even the next Bitcoin. You must understand the purpose of crypto is to replace money as a mean of trade. the value of the coin is not based on the coin supply, then we have the same problem like gold based currency. Rather the value that we all give to the crypto. same like how most of the country tie their currency to USD even though USD are not tie to anything.

So the value of the crypto is determine by us, not by the limited supply of the coin. The more people are regconise the coin, the higher the value of the coin is.