OpenwebUI (https://github.com/open-webui/open-webui) accepts openrouter API keys and will let you choose from all models on openrouter in a ChatGTP (or even slightly better IMHO) interface.
Did you refer to my submission? The goal here is to offer a more focused and user-friendly way to compare models side-by-side, which isn't as straightforward on the main OpenRouter models page.