As in viṭhapana विठपन - Illusory Creations or stṣṭhāna - location
他字門，入諸法處不可得故
The syllable ṬHA is a gateway because the location (stṣṭhāna) of all dharmas cannot be found.
Kumarajiva
入搋字門，悟一切法積集性不可得故
The syllable ṬHA is a gateway because the nature of being illusory creations (sarvadharmā viṭhapana) of all dharmas cannot be attained.
Xuanzang
咤(上)字門一切法長養不可得故
The syllable ṬHA is a gateway because all dharmas’ being illusory creations (viṭhapana), they are unattainable.
Amoghavajra
The syllable ṬHA is a door to all dharmas because of the non-apprehension of fabricated appearances (viṭhapana)
Conze
The syllable ṬHA [means] all mental phenomena are openings because of the non-recognition of the illusory creations (viṭhapana)
Jayarava