In https://pubmed.ncbi.nlm.nih.gov/9855498/ the average dose was a staggering 440mg a month (multiple rolls a month) with a sample size of 24 people. This is definitely falls under "heavy" usage and even then it's hard to disambiguate correlation vs causation in such a small, underpowered study.
The average participant in your second study, https://sci-hub.ru/10.1177/0269881106059486, had again taken an average of 800 lifetime doses. These are insane amounts and do not remotely reflect the average user.
Here's a meta study for example that found no long term impact among more realistic users - https://pmc.ncbi.nlm.nih.gov/articles/PMC3053129. I haven't looked into this in a long time, so I ran a deep research query, and for typical usage (<50 lifetime doses, months between sessions) there seems to be very little evidence of structural or functional harm.