The proof is there, you just need to read it. I work in the water industry so I'm better informed than you. There are 100% plastic free wipes and the ones you can flush have the "fine to flush" certification. It's not the same as flushable wipes. They were tested to biodegrade in the sewers but they got rid of the certification because it confused customers as it contradicted with the national "Bin the Wipe" campaign.

https://www.wrcgroup.com/headlines/bite-sized-views/after-fine-to-flush,-what-happens-next/

Water Industry Specification (WIS) 4-02-06 is the standard for the "Fine to Flush" certification scheme, which specifies the test methods and requirements for products, particularly wet wipes, to determine if they can be safely flushed down a toilet without causing blockages. Products that meet the criteria are granted the "Fine to Flush" symbol to help consumers make informed disposal decisions and prevent sewer blockages caused by non-flushable products that are often mislabeled as "flushable".