Good news, exposure therapy is quite effective for arachnophobia and is the first-line treatment. SSRIs do not have the same level of supporting evidence, and the effects are not as durable.
I mentioned it though as one of the most stark changes I noticed after getting on an SSRI was pretty much immediately losing my fear of spiders. It was the first sign I had that showed it was doing something.
I used to literally, on occasion, launch my phone across the room if I was scrolling and came across a spider (sometimes drenching myself with coffee or whatever in the process!) and then one day, shortly after getting on it, I stumbled across some awful tarantula video or something and I just stared at it like “huh, why am I not freaking out”.
To the extent that we can measure depression, SSRIs have been widely proven in gold standard phase III clinical trials to help with the treatment of major depression. What exactly is supposed to be lacking in the supported evidence?
The reality of the actual trial data was very different - with catastrophic results for many.
Also, see the debate around discussing traumatic events in therapy immediately versus waiting a year.
Throwing people in the deep end doesn't always result in a swimmer :)
YMMV of course.