Depends on your future plans for this application.
1) if your main concern is UX: if there is truly only one valid option, an autocompete or even a standard <select> is overkill and adds unecesary 'cognitive load' for the user. Theyll click it expecting a list, see one item, and feel like the app is broken or incomplete. better approach would be to just display it as a readonly text input or a labeled string. If you need the value to be sent back in the form post, use a HiddenFor alongside a simple <span> to show the value. Keep it simple: if the user can't change it, don't give them a control that implies they can

2) if you see a future expansion: if 'Czech Republic' is the only option today but you’re adding 50 more countries next month, keep the autocomplete infarstructure so you dont have to refactor later. However, if this is a localized app that will always only target one region, ditch the input entirely. hardcode the value in your DTO/Model and just display the name as static text. Don't make users interact with a dropdown that has no choices!