I have the book 'Lavi' by John Golan. It clearly explains how the airplane itself was quite something. Very capable. But the issue that let the whole program down was it's massive dependence on US funding. And how that was simply not going to work for the US since it would end up taking market share away from the F-16, which the Lavi surpassed in some areas.
It was not an issue of Israel over-reaching engineering wise or lacking the technology base for it, but rather an issue of the program being too expensive for Israel to afford on it's own when F-16s were available for them via FMS for almost free.
As for the Tejas program, I can only say one thing- it is the only reason why India today can work on the Tejas Mk1A, Tejas Mk2, TEDBF and AMCA, all programs together. It is a massive stretch as far as engineering resources go, but without the Tejas program, India would've been forever a license building nation.
I can write a whole lot on it, but will remain eternally grateful to the Indian politicians, scientists, technocrats and others who sanctioned the program, the investment into all the facilities that were needed to develop it and kept the will to keep going despite delays and missed deadlines. There were umpteen attempts made to kill the program, especially given how lucrative it is for foreign OEMs to get an order from the IAF even for a license built fighter.
JF-17 made a lot of people who never understood or yet understand the level of complexity in a fighter program, believe that Pakistan knew how to make fighters. They were both fooled and chose to stay ignorant.