OTOH, I'm still waiting for any pen-enabled Android apps that manage to catch up with XP Tablet PC Edition 2004 in terms of usability and feature set, let alone

OTOH, I'm still waiting for any pen-enabled Android apps that manage to catch up with XP Tablet PC Edition 2004 in terms of usability and feature set, let alone anything made for iPads (or Windows 8/10/11). Even desktop Linux is doing fractionally less worse.