Expect to lose at one point or another.
Whether it's making a bad call, or messing up a transaction, you should be financially and mentally ready to lose some.
You're not gonna win every battle, even if you're investing long term. And forget about buying low and selling high, you might be really lucky once or twice, but the odds of timing things right are very very slim.
Even hodling long term is not without its risks of losses. Nor is DCAing completely protecting you.
There's also a lot of ways you can lose your crypto. Exchanges don't just get hacked, but they can block your funds, or get shut down.
And don't forget about user error. No matter how hard you try to safeguard your private keys, it's not completely idiot proof, even on a hardware wallet.
It's easy to make mistakes. Sometimes it's not even a case of not being careful enough, but also being too careful. I heard a lot of stories of people with complicated methods to safeguard their 24 word phrase using decoders etc… When the time came to recover their phrase, they had no idea how they had scrambled and safeguarded the whole thing.
At some point or another, you will likely lose some. If you already know this now, it will be easier to deal with it when it happens, and you can already think of how much loss you can tolerate, and what you'll want to do.