Can’t create new blocks on Android WP app.

Self hosted
CentOS Stream 8 (I'm stuck with it for now)
PHP 8.2.22
Wordpress 6.6.1
Theme Twentyfourteen
Samsung GS10
Android 12
WP App 25.1 (deinstalled, reinstalled, rebooted)

Tested on 2 blogs on same host, though I don't think it's the server's fault.

I open the app, select which blog, hit "+" and "Add new->Blog post". So far, so good.

I type a title. Tap return, nothing happens, cursor stays in the title. Tap the "Start writing…" area, nothing happens, cursor remains in the title.

Tap the "+" to add a new block, menu of blocks appears, tap ANY block type, goes back to the edit screen, cursor remains in the title.

I can revert to the non-block editor and create a post. But that isn't really useful.

I can edit old posts, but I can't add new blocks to them.

I tried a different virtual keyboard on my phone to no effect. Disabling plugins also has no effect.

I even connected a BT mouse (same non-effect as tapping) and BT keyboard which allowed me to TAB to the "Start writing…" block, but I can't make NEW blocks, and the physical Enter key does nothing at all, can't even make a soft-break with Shift-Enter. Despite the cursor now being in the initial content block, the mouse can't control the cursor position except to send it back to the title block.

I don't know what else to try. Any ideas?