Shop subtitle taking unwanted values

You can hide the title on the shop page with some custom css:

.archive.woocommerce #intro.option1 .page-title {display:none}

If your theme does not have a setting where you can enter custom css, you can use a plugin like this one:
https://www.ads-software.com/plugins/simple-custom-css/

Changing the title may be possible but is more involved.

I can’t view your website, but it sounds like your theme has some weird methods of pulling in the title.

Perhaps Yoast SEO could help: https://www.ads-software.com/plugins/wordpress-seo/