You do not seem to have much knowledge of his publication record.
Here is a list of 272 journal articles by Einstein and coauthors, the majority of which would certainly be considered peer reviewed by modern standards.
From just these papers, among the things you put into the bucket of "not huge breakthroughs" were (in small length scales) Bose-Einstein statistics and Bose-Einstein condensates (notably his 1924 and 1925 papers), his atomic emission and absorption theory (the "stimulated emission" in laSEr), and his paper with Podolsky & Rosen and (in large length scales) General Relativity, Einstein gravitational lensing, the Friedmann-Einstein and Einstein-de Sitter expanding universe cosmological models.
> terrible record
> might have produced more
You do not seem to have much knowledge of his publication record.
Here is a list of 272 journal articles by Einstein and coauthors, the majority of which would certainly be considered peer reviewed by modern standards.
https://en.wikipedia.org/wiki/List_of_scientific_publication...
From just these papers, among the things you put into the bucket of "not huge breakthroughs" were (in small length scales) Bose-Einstein statistics and Bose-Einstein condensates (notably his 1924 and 1925 papers), his atomic emission and absorption theory (the "stimulated emission" in laSEr), and his paper with Podolsky & Rosen and (in large length scales) General Relativity, Einstein gravitational lensing, the Friedmann-Einstein and Einstein-de Sitter expanding universe cosmological models.