We should not invest in every coin because not all the coin will necessarily give you profit therefore greed should be avoided at certain stage as greed can compelled you to use any coin for investment.
Is possible to invest in every coin? I think it is impossible.
Sure, not every coin will give profits. Many of them even give the losses because they have no future. That's why we don't be greedy to invest in too many coins. Investing in too many coins won't increase the chance for gaining profits, it even raises the chance for higher losses. Especially if we invest in random coins, new coins, meme coins, or shit coins.
Newbies are more interested in investment in new coins because they are not familiar with the fact about scam projects.
Newbies think investing in any coin will have the same risk. They are mostly interested to invest in the hype coins, they read may media posted it. Because the hype of new coins is quite massively, it attracts the newbies to join the investment. They don't know if the hype coins will be too risky for them. They don't know that many new coins end up with scams.
If a person should start investment then there is no better option than bitcoin and Ethereum but if someone wants to initiate with lower value coin then doge, Solana, XRP and ADA are good choices so they should not forget about investment in these coins.
Bitcoin and Ethereum are the most recommended coins for investment. I exclude Doge for the beginner, it is very high risk to invest in meme coins. Although it is a part of the top coins, Doge will always have no fundamental as other meme coins.