APPLE TV 4k without USB

there is no way to fix this issue.

There is a way, of course, but not as self-reliant as for the models that do have USB.

Restore your Apple TV - Apple Support

“If you have an Apple TV 4K

If you see […] a flashing indicator light on the front of your Apple TV, contact Apple Support.”

You will need the assistance of an Apple technician (i.e. bring it in).

A phone number for Spain is listed on:

Contact Apple for support and service - Apple Support

This is a user

helping other users with tech questions forum, you are not addressing apple

here  just  fellow users

you can complain to them using their feedback channel

Feedback - Apple TV - Apple

first I would read though

Reset or restore your Apple TV to its factory settings - Apple Support