SQL Server 2019 standard edition CDC with SSIS standard edition
You should research DMS solutions. AWS DMS, Azure DMS, and HVR DMS are the three I'm familiar with. They use CDC, are not just for migrations, and are very good for on-going replication of data where you don't have primary keys on every table or you are going from SQL to something else. HVR is probably your best bet of these three since you're going from SQL to Postgres but I know there are additional DMS products out there. Here's a link to get you started:
https://www.hvr-software.com/platforms/postgresql/