Sothing that I foud

Because that’s the way lossy optimization works. It’s much different than lossless, where no data is discarded, thus you can only optimize once (unless someone else has a better compression algorithm, like stock libjpeg vs. mozjpeg.
With lossy, you’re throwing away more data every single time. That isn’t desirable generally because you’re losing more quality with every single pass, so I tell folks to be careful that they don’t re-optimize with the lossy options.

Very good question though!

So, is there a way to use use lossy image optimization with ewww? Believe me or not, few months back I was doing some testing on a test vps runing on nginx + nginx_pagespeed (by google) and there are lot of in built image optimization modules built into pagespeed (even converting to webp when for supported browsers) and even the pagespeed also does lossy image optimization.

Which I think perfectly fine for the size of images gets used in website. You are not going to zoom in and do crazy stuffs with it. But even though with lossy optimization of both tinyjps/png & pagespeed. I barely noticed any difference from a normal distance from my computer screen.

Also honestly I believe if a picture look slightly lossy in human eye but it it helps the site loads faster as the overall size of the website will reduce, people will be more happy with the faster site than a slow website with crispy images.

So, again, is there any way to get the exact optimization level that tinyjpg or tinypng provides with ewww?

Yes, EWWW uses TinyJPG/PNG when you turn on the Lossy options on the basic settings page (only if you have a Cloud API subscription).

I’ve used mod_pagespeed as well, and it is a bit limited. It just drops images to a specific jpeg quality level, which is nothing at all like TinyJPG/PNG, where they uses more intelligent methods of scanning an image for the best ways to save space without sacrificing quality.