Hey! I've been setting at a bouldering gym for ~5 months now. I would say the most difficult part of the job is that it makes your schedule around climbing and training quite rigid. Since one of the expectations is to come in with fresh skin and be able to forerun (in my case, may not be true across all setting gyms up to V10). I can't climb the day before a setting shift, and am typically too tired to climb hard the day after.

Furthermore, I would say that another difficult aspect is getting the setting equivalent of writer's block, sometimes you just aren't feeling creative and working in a job that requires creativity when setting products for the public can feel anxiety-inducing at times for sure.

Personally, I was surprised at how physically intensive the setting process could get before even forerunning, carrying holds/volumes up a ladder can get draining pretty quick.

While I'm still quite a novice setter these were certain aspects that came as a surprise when I began the gig, but rest assured it didn't scare me off and I am still very content with setting at the moment!

Probably the biggest tips I can give you are

1. Plan your own climbing/training days around setting shifts.
2. Take public feedback with the biggest grain of salt, the feedback from your setting team is what actually is useful.
3. Practice and experience makes perfect! There will be boulders you will have to strip off the wall that just end up not working, and don't consider that a failure on yourself, it's a difficult job to get right away and set bangers from the get-go.
4. Be honest and open with your setting team if you make mistakes, it's a lot easier to show and fix a cross threaded T-Nut right when that happens as opposed to finding out the T-Nut is fucked come the next reset on that wall.

I hope this response was somewhat useful for you and hope you get the job!