How can I unlock my iPhone 5s if I remember the iCloud and not the passcode?

Hello,

I see you have a disabled older mobile device.

When running a mobile device OS version lower than 15.2, follow the directions in this support article --> If you forgot your iPhone passcode - Apple Support

If you do not have a computer, use this link Find Locations to find an Apple service location, or ask a friend if you can use theirs.

This will result in erasing the iPhone. You can, however, restore it from a backup as described in this support article --> Restore your iPhone, iPad, or iPod touch from a backup - Apple Support

Here are resources if you are prompted for your username and password and have forgotten them:

If you forgot your Apple ID email address or phone number - Apple Support Note that typically this is an email address you use.

If you forgot your Apple ID password - Apple Support