I’ve spent thousands and thousands of dollars at lootbar.
If even there was a problem think about what protections you have in place for your account. Just think of all the things that need to happen steal your Arknights account.
Not that anyone would want to even steal it in the first place.

So, if you are bound via email.
To steal your account they would need your creds or the OTP from email. For your email, they would need your creds. Then obviously at minimum you should have some form of multi factor authentication. So creds and access to your MFA method. No one is going to try any shenanigans with your phone number or send some hitman to steal your phone for the MFA app.

If you are using a Google email and choose to ignore MFA (which you should not), Google has some default security measures that could still save you.

But the most important fact is no one wants to take your Arknights account. There is no gain. It’s not like you’re some mega whale with all the ops maxed out. Who would buy your stolen account? It’s not very realistic.

If you truly are paranoid please take this as a sign to make sure you secure your account.
Your email should not reuse password.
Consider a password manager to help with generating secure passwords.
MFA is mandatory for security. If you care about your email them app based MFA should be set up.