Yes you are right it is smart choice to be careful when investing in Bitcoin. And to reduce risk keep Bitcoin in multiple wallets. If we have a lot consider a safe option like hardware wallet. But even with safe wallet we still need to be careful. Before investing we should take time to learn and understand the market. Some people might say to invest little at a time DCA but it's better to be cautious and avoid losing more money. Bitcoin price might drop even lower so it's important to wait for a better time to invest. But if we will use the DCA method so it is not important that where the Bitcoin is and what is the price of it.
Keeping Bitcoin in a hardware wallet isn't the only thing to look after, the back up seed phrase/ recovery phrase and the associated private keys is very important factor for safe wallet. I saw a post on X where a guy posted an advert for any person who saw his hardware wallet, he is offering to to give the person some amount and form the look of things, he didn't do a proper backup where his funds were kept else he would have just move the fund to another safe address instead of looking for the loss wallets and his house key.
DCA is one of the best and safe way to buy Bitcoin but the problem is not everyone has free money to buy consistently as the market drop, but if OP has the cash flow to buying as we dip, it will help him big time instead of buying at a spot when the next direction is not certain yet. But emphasis of wallet back up shouldn't be underrated.