A combination of measurements of the 𝐶⁢𝑃 properties of Higgs boson interactions with electroweak gauge bosons is presented, using 140  fb−1 of proton-proton collisions at √𝑠=13  TeV recorded by the ATLAS detector. Results from vector boson fusion 𝐻→𝜏⁢𝜏/𝑊⁢𝑊*/𝛾⁢𝛾, inclusive 𝐻→𝑍⁢𝑍*, and 𝑊⁢𝐻,𝐻→𝑏⁢¯𝑏 channels are combined. No evidence of 𝐶⁢𝑃 violation is observed, and constrains on the 𝐶⁢𝑃-violating operators in the Standard Model effective field theory framework (SMEFT) are set in the Warsaw basis. The results from the combination improve by over 40% on previous individual limits on 𝑐𝐻⁡˜𝑊 and, for the first time, simultaneous constraints on three coefficients 𝑐𝐻⁡˜𝑊, 𝑐𝐻⁡˜𝐵, and 𝑐𝐻⁡˜𝑊⁢𝐵 are set. These limits are the most stringent constraints to date on the relevant Wilson coefficients in the SMEFT framework with minimum model dependence.