You can use your external-server Cron Jobs to import yours listings automatically to your WordPress e.g. once per day at midnight.
1. Register - https://cron-job.org/

2. Check your email and activate account

3. You will see message "Your account has been activated successfully". Click login link and login

4. Visit Cron Jobs and Click "Create cronjob"

5. Visit MyHome IDX Broker > "Import listings assigned to your account" page

Copy first link

Add it here and set once per day:

Click "Create cronjob"
To make it works correctly you need to add second cronjob. Click "Create cronjob" again

Copy second link

and schedule it every 1 minute

Listings will be automatically synchronized every 1 day.