The spindly nature of Computer Modern that you see on computer screens is because of a poor translation of Knuth's Computer Modern design (whose default parameters were tuned taking into account the amount by which ink spreads on the page, on the printing devices Knuth was targeting) into outline fonts (which do not take into account the fact that there's no ink spread on the screen). See for example https://tex.stackexchange.com/a/361722/48
The problem is that most documents set in Computer Modern are not read on paper but on screens, where its legibility is very poor due to the extreme contrast between stroke widths.