Was there ever a time when tech companies were not overvalued?

Hello! I'm a new index fund investor trying to learn about single company's stocks. I assume one of the important things to learn is to find out if the company is “rightly” valued. P/E metric I believe is one of many ways of checking the valuation. Right now for all the big tech like Apple, Microsoft, Amazon, I see their P/E is high meaning they are overvalued? When I see comments on this sub, they express a similar feeling of most of the companies being overvalued.

So, when were the companies not overvalued? Big tech specifically maybe.

Thanks!