Instead of looking for those passive staking products, I suggest you either try to find another job that pays in Bitcoin or allocate some of your salaries to buy Bitcoin regularly. That is arguably more secure than any centralized product right now and you have control over how much you spend. Obviously don't overspend on your investment, even $10 a month is fine as long as you can take the risk if anything went wrong.
Some people also suggest value cost averaging instead of doing DCA, you can check them out if you're interested in more investment alternatives.
Even if you keep bitcoins in your wallet, there is no 100% guarantee that it will be absolutely safe. There is no safe way to profit from your idle bitcoins, it is best to continue to keep bitcoins in a non-custodial wallet.
I think you're referring to protecting the seed itself, which might be different from the risk most people are talking about here. Using a cold wallet (not necessarily a hardware one) and good security practice to protect your seed/private key is probably one of the safest methods to guarantee that you don't lose your coins. CMIIW.