AnyDesk officially dropped support for Windows XP years ago. If you encounter bugs, their support team will likely not be able to assist you.
Furthermore, the AnyDesk 6.x versions compatible with XP no longer receive feature or security updates from the developer. AnyDesk has since moved on, focusing its patching efforts on versions 7 and 8. This means that even if a vulnerability is discovered within AnyDesk 6.x itself, it will likely never be fixed. Consequently, using AnyDesk on XP is recommended only for —never for a machine directly connected to the internet.
For "full features" without needing someone at the XP machine to click "Accept": Open AnyDesk on the XP computer and go to Unlock Security Settings (requires administrative rights). Enable unattended access and set a strong password.
If you cannot get AnyDesk to work, or if security is too high a risk:
A: Increase the timeout in Settings → Security → "Idle session timeout" to 0 (never).