Is it a good idea to buy some crypto for long time investment plan from exchanges such as binance as keep it there, any alternatives ? Because i have heard bad things about some famous exchanges such coinbase.
Nope, it is definitely not a good idea for long-term investments. As far as I know the current exchanges on the market are not insured by any financial authorities. So in case they lose access to your Bitcoin you will be left with NONE and you won't receive any compensation.
If I were you I would keep funds on exchanges only as long as I am trading with them.