Well, you make your password for your password manager to be really strong - you will only ever have to remember that password (and how to open your device). You could take the lyrics to the first verse of your favourite song, for example, and use the first letter of every word. Include any speech marks and change vowels for numbers/characters - for example change o to 0, i to ! etc. I see that my password manager recognises that my device has facial recognition abilities as well (new iPad) and I can add a keypad number but sometimes, it will also ask for the password.
You make sure that your password manager password is much stronger than that of your laptop/device. As it stands, if someone can get into your laptop, and you allow your laptop to remember your passwords, all your online world is available.
Someone else getting access to your device has to open your device and then add your password manager ID and password as well to obtain your passwords, that is an extra step.
However, your password manager password is only ever used locally on your device. Your user ID and password is used to encrypt everything you put in the password manager. Afterwards, your password manager uses military grade encryption to encrypt your data before allowing it to be sent over the internet (also using a Virtual Private Network - encrypted link - part of the password manager security). The password manager stores your encrypted data - it has no access to your data, because of the encryption.
So yes, the only weakness is if you let someone else have your unlocked device and Password Manager Password/user ID Also, if you lose your password you lose all access to your data.
Probably not of interest to you, but you can add the password manager to all your devices so it is available on a desktop, laptop, tablet and mobile phone. In this case, you can access your password manager from all the devices, you won't have to look them up to add your existing accounts.
Password Managers are quite expensive but I prefer the peace of mind and the fact that my password manager provides a way for me to securely grant access to all my data to named family in the event that I am no longer capable.