Thanks very much for all the help.
With your effort, I could isolate the issue and track it to ESP_DISPLAY_PANEL.
I spent a couple of hours circling it with the AI from deepWiki, but also without finding a solution.
So I ended up opening an issue on Git (well… I had the AI write it… all a bit complicated for my level…). Let’s see if that helps.
Meanwhile I’ll use UART and workarounds.