Interpretability-by-Design with Accurate Locally Additive Models and Conditional Feature Effects. - Vasilis Gkolemis; Loukas Kavouras; Dimitrios Kyriakopoulos; Konstantinos Tsopelas; Dimitrios Rontogiannis; Giuseppe Casalicchio; Theodore Dalamagas 001; Christos Diou (CoRR, 2026)