How to replace the Hero image in Twenty Twenty-Four (TT4) – and the Cover Block bug that blocks it

Hi everyone,

I'm working on a new project using the default Twenty Twenty-Four (TT4) theme and I'm trying to replace the Hero image on the front page with one of my own images from the Media Library.

However, I've run into a problem that I can't seem to solve on my own.

What I tried:

I uploaded several images to the Media Library.

I opened the Site Editor (Design → Editor) and selected the Home template.

I clicked on the Cover block (Hero area) to select it.

I tried to replace the image via the block toolbar – but instead of the expected "Replace" option, I only see "add-media".

When I click on the Media Library, nothing happens at all – it doesn't open. I also checked the three-dot menu in the block toolbar, but it only shows the standard options (copy, cut, duplicate, add before, add after, copy styles, paste styles, group, lock, rename) – no image-specific settings.

What I found out so far:

After some research, I came across a known bug in the Cover block of Twenty Twenty-Four. When the Cover block is set to use the Featured Image, critical settings – such as image resolution or "fixed background" – are hidden, and the block sometimes behaves as if no image were loaded at all. The official workaround is to:

Add a new Cover block.

Insert a temporary image (not the featured image).

Adjust the settings (e.g. resolution to "Full Size").

Save the block/template.

Then use "Replace" → "Use Featured Image".

My problem now:

I can't even get to step 2, because the Media Library doesn't open in the Site Editor when I click it. I suspect a plugin conflict (possibly LiteSpeed Cache or a security plugin blocking the JavaScript).

My questions:

Has anyone else experienced this with TT4 – the Media Library not opening in the Site Editor?

Is there another reliable way to insert a temporary image into a Cover block (e.g. drag & drop) without using the Media Library?

Which plugins are known to cause this kind of conflict in the block editor?

I'd really appreciate any hints. I'm very close to solving this, but I feel like I'm missing one final step.

Thanks a lot in advance!