Constant feature ansatz validation for the Modal estimator, showing the effect of ISW-lensing and point source subtraction for ℓ< 300 (left panel) and the impact of a lower ℓ maximum cutoff on the average signal (right panel), i.e., lowering ℓ_max = 2000 to 1500 (T) and ℓ_max = 1500 to 1000 (E). All Modal 2 results in Sect. 8 have used the extended common mask, except the validation analysis at different resolutions (right panel) which for consistency employs the common mask.