Note that above we introduced the subscript s to refer to the use of structure-based molecular representations and the corresponding baseline ML model is denoted with K s . Furthermore, a model termed K p based on electronic properties computed at the semiempirical GFN1-xTB level was developed, with the corresponding representation x (i) p (see below for details). Finally, a model K sp is explored, that combines the two kernel functions as K sp (i, j) = K s (x