My suggestion to you is, first, start with fresh portfolio, like you will convert all your altcoins to stable coin or btc, because most of the coins now are btc/usdt pair, 2nd, choose the best exchange with good volumes and learn how exchange work, how to set buy orders and sell orders. 3rd, learn the basics of trading, like how to identify supports and resistance. Last, don't believe to anyone in crypto, you will go in this battle alone, just learn and keep studying how to trade.
By far the best advice that you gave is the last one, when it comes to investing everyone is looking for the same thing and so you cannot rely on anyone else, if you want to make profits then you need to find a way to do it for yourself otherwise you will lose money or in the best case scenario your profits will not be as good as they could be, but that rule not only applies to this market it applies to all of them, sometimes I wonder what are people thinking when they invest in a stock just because someone on TV recommended that stock in one of those financial television shows as if they did not know that the person giving that tip probably bought that stock for cheap and then he will sell it for big profits later once the show is broadcast.