Dear,
1. That problem because your site is missing google map settings, i have go to 'Jobmonster -> Settings -> Location' and add google map setting 'Starting Point Latitude, Starting Point Longitude, Default Zoom Level' Now it's working.
2. If you want use custom apply job url, please go to admin menu 'Jobmonster -> Settings -> Job Application' and change setting 'Enable custom application link' to 'Yes, on both dashboard and frontend' Then go to edit job, you will see 'Custom Application link' to add custom apply link for job.
3. I have check your site, i see that problem because conflict with datetime picker in Rank Math SEO plugin, You can deactivate Rank Math SEO plugin and check again.
I see when edit Job not have date field of Rank Math SEO plugin but it always load datetime picker plugin and it conflict with datetime picker use in Jobmonster theme.
To resolve your problem you can contact with Rank Math SEO plugin author help you to load datetime picker if have date time setting of plugin or you can switch to other SEO plugin example Yoast SEO plugin.
Best regards.