I have a site on DreamHost shared hosting:

<li>Joomla 3.9.13
<li>PHP 7.3.11 FastCGI
<li>Misc extensions, including Gantry 5.4.31, RokCommon 3.2.8, RokGallery Module 2.45, RokNavMenu 2.0.9, RokSprocket 2.1.26, Advanced Module Manager 7.12.3, etc.

With K2 2.9.0, I can follow a K2 category link, and a list of items in that category are displayed, as expected. After upgrading to K2 2.10.0 or 2.10.1, if I follow a K2 category link (or manually enter the URL for the category; same difference), I see a page with the category title/name, with blank body (no list of items in that category). Downgrading to 2.9.0 immediately resolves the problem.

Any ideas/suggestions?

Thank you!

Hi Fotis,

Thank you for responding!
I had already set error_reporting to maximum and debug enabled (1). I have the third-party extension, Additional Categories for K2, which results in "Deprecated: Methods with the same name as their class will not be constructors in a future version of PHP..." when enabled. That's the only warning/error that appears. Before starting this topic, I had already disabled that extension (component + plugin) with no apparent effect (other than no more warning/error). The K2 category pages still appeared blank (except for K2 category title).
After you replied, I tried disabling many/most third-party extensions (components, modules, plugins) for testing/troubleshooting. Unfortunately this made no difference. I'm not sure what else to try...

Thank you, Fotis!

The trouble was related to "Additional Categories for K2." Apparently it's not compatible with K2 2.10.x. In my testing, at some point I created a new item and assigned it to a category that appeared blank (front end listing) after upgrading to K2 2.10.x. The new/test item appeared in the front end listing. Filtering items by category in the back end, I realized items that had been assigned a secondary/additional category no longer appeared in secondary/additional categories.
As you recommended, I purchased a "multiple categories" pro subscription. The extension is working well.