… the site has been designed on wordpress.com using theme and plugins which apparently will not migrate to www.remarpro.com,
The reason you may not be able to migrate the theme is a commercial licensing issue, and not a technical one.
The site you linked to uses the commercial “Avada” theme. And Avada uses its own custom page builder plugin (called Fusion Builder), which you used to build the site… and not WordPress’ own native editor.
So the content “lives” in the theme and its editor plugin, that’s why you’re unable to transfer the content without the theme (and its bundled plugin).
Now if you can install the Avada theme and all the required plugins (including the Fusion page builder plugin) on your WordPress site at Siteground, you should be able to move easily migrate the site without re-building it.
How did you come by the Avada theme?
— Did you purchase the Avada theme yourself and uploaded it to WordPress.com? If so, then you can simply upload the same theme files to your WordPress site at Siteground.
— Or did you purchase it from inside WordPress.com? If so, please ask WordPress.com support to see if the license allows you to re-use the theme you purchased when you move your site to another host.
— Or was it provided by WordPress.com as part of your subscription? If this is the case, there’s still hope: but you’ll have to purchase the theme directly yourself, install it at your new host, and you should be able to restore the entire site.
I thought migration is an easy process but turns out it’s a total PITA for a non-developer.
Migration is actually faily straightfoward, and you certainly don’t need to be a developer.
And the challenge you’re facing is NOT really because you’re migrating from WordPress.com to a self-hosted WordPress site (aka www.remarpro.com).
How can I be so sure?
Just switch themes and see what happens: even without migrating to another host, you’re likely to face exactly the same problem (missing content) when you simply change themes and disable the Fuson Builder plugin that was installed by your Avada theme.
So the root of your problem is because your chosen theme “Avada” uses a custom editor or page builder, and doesn’t store the content the usual way WordPress stores stuff. That means you’ll ALWAYS NEED TO USE this theme (and it’s custom page builder plugin) if you want don’t want to lose your content.
Once you build your site with these 3rd-party page builders (and the themes that require them) — and that includes Elementor — you can’t simply switch to another theme without doing substantial work.
This is the unfortunate trade-off people don’t realize they’re making when they choose to use these fancy themes and 3rd-party page builders.
Good luck!