I usually Invest a very small amount of bitcoin to another coin because I know this time is very crucial to invest in any new coin or even in an old coin.
Any suggestion from your side which is good for long term
If you have 1 BTC, you should just leave it in BTC, don't think about altcoins. Everyone dreams of having 1btc is difficult and if you already have 1btc you should hold it to invest in altcoins.
Even if you still want to invest in Atlcoin, don't touch the 1 Bitcoin asset anymore. If you sell some Bitcoin to invest in Altcoin, you will regret it later. You have to look for additional funds to invest in altcoins. Maybe this is wiser and good altcoins for the long term in my opinion are ETH and BNB.