Do the Salaf believe that Allah has a limit known only to Him, as Imam Al-Darimi mentioned, and is the statement that Allah is not confined by directions considered an innovation?

The terms "limit" (حد) and "direction" (جهة) are ambiguous expressions not found in the texts of Islamic law (Sharia).

So, whoever applies "limit" to Allah and intends to affirm His existence and His distinctness from His creation, then this is correct. But whoever intends that He is limited by creation, then that is false. Allah Almighty has a limit that no one knows but Him, and He is upon His Throne, above His heavens.

Likewise, concerning "direction": whoever intends by it to affirm Allah's highness (uluw), then this is correct. But whoever intends to confine Allah to a direction that encompasses Him, then that is false. For Allah is in a direction of highness that does not encompass Him, and what is above the Throne is non-existent; there is nothing there except Allah.

Thus, the statement of Al-Tahawi: "The six directions do not encompass Him" is true in the sense that none of His creatures encompass Him, not in the sense of denying His highness and His being above.

It is better not to use these terms due to their ambiguity and potential for misinterpretation.