Remote login MacBook Pro to iMac - both computers use Catalina

Please define 'remote login' since that has many flavors.

First, is 'remote' from across the room (i.e. over the local network)? Or remote (across the country)? That's a big factor right there.

Secondly,

Are you looking for a command-line login over something like SSH?

Are you looking for file sharing login, where you can access files stored on the iMac?

Are you looking for full-screen sharing where you can see and manipulate the iMac's desktop?

All of these have different components, but all are considered 'remote login'

The easy way, is to setup TeamViewer.com

Configure the TeamViewer.com app on the at home computer so it is always running, and will let you connect without needing someone to approve the connection.

You could try to setup a VPN server on your home network, and allow you to make a VPN connection to your home, and then screen share across the VPN connection. Non-trivial.

You could open ports in your home router that allow screen sharing into your home network. Non-trival and higher risk factor.

TeamViewer.com has always been an encrypted connection. Just make sure the connection authentication you setup is nice and strong.