What did Siegel and Shuster think about later writers and artists takes on Superman?

Hey been wondering this for awhile so I wanna ask. Did Siegel and/or Shuster ever voice their opinion on how Superman and his world developed after their original run on the series concluded when Siegal was drafted?

I'm obviously aware that their vision and original interpretation is very different to how the character developed and that many core concepts were added to other creators even during Golden Age; alongside the fact Siegel and Shuster regretted selling the character and attempted to reclaim ownership largely due to losing creative control over their own creation. Siegel apparently was under editorial regulations during his return to the book from 1959-1966; so had little to know say in the actual direction of the stories or how the character he created was presented.

But in addition to their already well documented attempts to regain copyright and control of the character; did Siegal and Shuster even voice their opinions on what they thought of later comics and adaptions quality wise? And have they ever discussed how they would have developed and constructed the property if they had full creative control either from the start or later on?

Thanks for any answers as I'm very curious about this.