Deprecated: json_decode(): Passing null to parameter #1 ($json) of type string is deprecated

I am having a couple of problems with the updated Medico template since migrating to the Joomla 4 version.

1. This error is appearing at the top of the page. (On mobile, it remains visible; on desktop it flashes briefly):
   Deprecated: json_decode(): Passing null to parameter #1 ($json) of type string is deprecated in .../templates/shaper_medico/features/logo.php on line 35

2. Each page shows a flash of layout without formatting before the page loads fully.
   The console error shows this message:
   Layout was forced before the page was fully loaded. If stylesheets are not yet loaded this may cause a flash of unstyled content. File referenced in the console is media/vendor/query/js/jquery.min.js:2:85519

3. Another warning
   This page uses the non standard property “zoom”. Consider using calc() in the relevant property values, or using “transform” along with “transform-origin: 0 0”.

Thanks.