In my location, when I request an agent through the chat bot, I see an option to chat with an agent as well, but that option apparently did not appear for you, unfortunately.
The email form you reached does seem promising, though I do not have the same "visually impaired" options available on the ebay.com site, though I do see them on ebay.co.uk.
The response to submitting your form appears to be identical to the response that eBay sends when users send unsolicited feedback about site feature changes, rather than something that is related to customer service, though. Unless you get an actual response to your message, I would not necessarily assume that your form was actually seen anyone.
I think at this point I think you have exhausted your contact options, at least on ebay.co.uk. Perhaps try ebay.ie or ebay.ca or ebay.com.au? I think those are all the other English-speaking sites.
You may be better off reaching out to eBay via social media.
When you say "customize the search engine to display prices in USD", are you referring to this?
When I search in the US and use the search customize feature found on the search results page where users can change between List and Gallery view in the upper right corner:
I see some options, including the option to convert prices to US dollars:
What you see may depend on your actual location, but that might be worth checking or unchecking that box and applying the changes, particularly if it shows anything other that US dollars.
