OK, so let’s dive deeper then.
Can you enable the WP_DEBUG mode and check if you get any PHP, error ?
You did not post your system infos yet.
Can you post them in your next reply ?
Are you able to upload a logo from the live customizer with another theme like Twenty Nineteen ?
How big is your logo file ? Did you try with a smaller file ?
the logo works on other themes
back to the logo issue – With the update, the logo now works, HOWEVER, I cannot change it.