How to remove remote management log in from my MacBook Pro 2019

That depends on the remote management system in use.

Many of them have safeguards that specifically hinder removal, precisely because it acts as an anti-theft device, allowing them to locate the device and prevent a malicious user from wiping the system.

Generally the management system has a central console (typically managed by your employer/school/whoever installed the management software), and they need to release the machine from the central database before you can do anything, so checking with them would be a good first step.