I know someone, personally, who has suffered from these treatments and now regrets having ever taken them.

n=1 is not a representative sample. many people suffer from medical treatments and regret having them. if you can show me that the percentage of people who regret trans treatments are dramatically higher than people who regret _any_ medical treatment, maybe then you'll have an argument.

Yeah, I was watching a gender doctor on youtube who was saying something like 'suicide rate in trans people who don't go on HRT as a teenager is 40%, so we put teenagers on Lupron and send them to therapy until they're sure if they want to transition or not. Increased chance of osteoporosis in old age isn't much of a risk compared to 40% suicide rate' (my words from memory, not a direct quote)

What's the suicide rate in people who do take the treatments?

From memory, he was saying that people who go through some kind of trans affirmative procedures have a dissatisfaction rate of 5% and this is likely to be lower than the complication rate.

I think I watched the first hour, here's the video: https://youtu.be/qGuvDlYDNzU, I'm sure if you're inclined to be critical of trans healthcare then it would be possible to make counter arguments to things that he says.

My perspective is; There seems to be concrete evidence from neuroimaging studies that transgender people's neuroanatomy more clearly matches the identified gender than the chromosomal gender. This is corroborated by anthropological and epidemiological evidence.

Clearly it's a complex issue and I think it could be quite possible to put cisgender people whose sense of gender was badly traumatised on hormone therapy as a teenager and cause them problems later in life. However 40% suicide rate in trans people is not something to be ignored