Lorentz and Einstein had similar realism ideas

FitzGerald and Lorentz first derived, independently, the length contraction as a logical consequence of the Michelson-Morley experiment showing a constant speed of light. Then Lorentz developed a more sophisticated theory where the contraction is also explained by electromagnetism pulling atoms closer together. Einstein later called former a principle theory, and the latter a constructive theory.

Mathias Frisch wrote Mechanisms, principles, and Lorentz's cautious realism in 2005:

I show that Albert Einstein’s distinction between principle and constructive theories was predated by Hendrik A. Lorentz’s equivalent distinction between mechanism- and principle-theories. I further argue that Lorentz’s views toward realism similarly prefigure what Arthur Fine identified as Einstein’s ‘‘motivational realism.’’

Many discussion of crediting Einstein for relativity are based on Einstein avoiding the constructive theory in his 1905 paper, and sticking to the principle-theory approach that Lorentz had earlier.

Frisch's paper further shows that Einstein's views on relativity were pretty much the same as Lorentz's.