I agree with you, if we holding coin on the exchange will be many risks like coin hack, exchange stopped and other problems.
I recommendation use hardware wallet like ledger or trezor because of high security.
But you must keep the 24-word seed to recovery.
Even with the exchanges our funds were secure. For this we need to select the best exchange service, because one with the best reputation will never let their users get scammed or get into any security issues. Holding on exchanges and different trading platforms were good for daily traders.