I don’t use any customizations.
Here’s what happened when I use the “Upload a zip”. Seems like WordPress should do some kind of temp “update in place” validation, then overwrite as a second step. Surprised this wasn’t push-button like plugins.
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Unpacking the package…
Installing the theme…
Destination folder already exists. /home/content/99/10800299/html/wp-content/themes/catch-everest-pro/
Theme install failed.