to solve just open file public_html/storefront/controller/pages/checkout/guest_step_1.php
find method _validate ( line 632)
You need to replace
        if ($data['country_id'] == 'FALSE') {
            $this->error['country'] = $this->language->get('error_country');
        }

        if ($data['zone_id'] == 'FALSE') {
            $this->error['zone'] = $this->language->get('error_zone');
        }
with this
       if (!$data['country_id'] || $data['country_id'] == 'FALSE') {
            $this->error['country'] = $this->language->get('error_country');
        }

        if (!$data['zone_id'] || $data['zone_id'] == 'FALSE') {
            $this->error['zone'] = $this->language->get('error_zone');
        }

This is indeed a great idea for an extension! Since there isn't an existing extension that meets your needs, it might be best to hire a developer to create a custom solution for you.

I have been trying to figure out how a customer can preview their uploaded image in the product section before placing their order so they know it is the right image they want on some of my personalized items as well as the check out page, but cannot figure out where to initiate the script for it. I can do it adding a script to the page itself using a block, customers can preview their image, but it won't add it to the order because it is not part of the Abantecart image upload script attached to the actual product order form. I also cannot find an extension for it.

This just started I'm I'm getting a broken page like this not sure why because I didn't do any code changes or anything. See if you can replicate this problem and my customers are emailing me with this problem

Hello,
I understand you're interested in running a WordPress plugin on AbanteCart. Unfortunately, this is not directly possible as AbanteCart and WordPress are separate platforms with different architectures and plugin systems.
The plugin you linked (3DPrint Lite) is specifically designed for WordPress and cannot be directly integrated into AbanteCart. AbanteCart has its own extension system that is not compatible with WordPress plugins.
If you're looking to add similar functionality to your AbanteCart store, you have a few options:

Check if there's a similar extension available for AbanteCart in their marketplace.
Consider developing a custom extension for AbanteCart that provides the features you need.
If possible, you might be able to use an iframe to embed a WordPress page with the plugin into your AbanteCart site, but this would require additional setup and may not be ideal.

For the most accurate information on potential workarounds or alternatives, I recommend reaching out to the AbanteCart community forums or contacting a developer familiar with both platforms.
I hope this helps clarify the situation. Let me know if you have any other questions!