Are you aware that Tom Prince has discussed and posted about his cycles online quite a bit and the man himself claims he relied heavily on test and deca and didn't even use tren after 1998...
Of course, he may not be telling the truth, but unless you watched him take his shots then I'll go ahead and take his word over yours.
Of the others you mentioned only Flex has had documented kidney issues. And these guys were all 1990's competitors who relied heavily on diuretics.
There is little evidence of any direct nephrotoxicity of trenbolone. There is a metric fuckton of evidence that carrying a lot of extra mass + GH + AAS will result in high BP for most people. High BP, if not controlled, can cause irreversible kidney damage over time. Add in rec drugs, diuretic abuse, and the high doses of NSAIDS many of these guys took to deal with joint pain and you have a recipe for kidney damage.
I would really like to see your evidence for this "tren will destroy your system" BS.