Source: Google
Google Chrome's password manager isn't as robust as what's available. One shortcoming is you couldn't add passwords yourself. You'll have to wait for the browser's prompt. But that might change soon. Android Police noted that the latest stable version of Chrome has a buried flag that allows you to manually add passwords.
A Reddit user spotted the feature in the Canary builds of Chrome at the end of 2021. The same user also spotted a recent Chrome Canary 101 feature, which lets you add notes for passwords. It's another feature unavailable on the current Google Chrome iteration.