the (English translation) of the lecture of David Hilbert at the International Congress of Mathematicians at Paris in 1900 (with the list of “Hilbert’s problems”) is here
Felix E. Browder. Mathematical Developments Arising from Hilbert Problems. Proceedings of Symposia in Pure Mathematics. XXVIII.2. American Mathematical Society.
Lectures by Hilbert on physics and especially on general relativity are collected here:
Tilman Sauer, Ulrich Majer with Arne Schirrmacher, Heinz-Jürgen Schmidt (eds.), David Hilbert’s “Lectures on the foundations of physics”, 1915-1927 : relativity, quantum theory and epistemology, Springer 2009
Around pages 417, 423 there is discussion of “Weltgesetze”, roughly what today in fundamental physical might be called theories of everything, with some remarks comparing to the perspective of Hegel in the Science of Logic.
Naturerkennen und Logik, Lecture at the Kongress der Gesellschaft Deutscher Naturforscher und Ärtze, 1930 (pdf, audio),
see also Eugene Wigner, The Unreasonable Effectiveness of Mathematics in the Natural Sciences
Cassirer liked to tell the following story: once he met the great mathematician Hilbert, the “Euclid of our time,” and asked him about one of the latter’s disciples. Hilbert answered: “He is all right. You know, for a mathematician he did not have enough imagination. But he has become a poet and now he is doing fine.
(from archive.org/details/philosophyoferns033109mbp)