500mg/week is not TRT, it's a steroid cycle. For many guys, the same applies to dose of 250-280mg/week. I'm not sure who your sources are, but they certainly aren't doctors who specialize in TRT. I'm not trying to be a dick either, I'm really not. It doesn't bother me at all if people want to use steroids, but there's no way that somebody is within the physiological range while on 500mg/week...or anything close to it.
Most guys on TRT do great in the 100-200mg/week range, some need even less. There are some instances where a guy may need more than 200mg/wk for TRT, but it's far from the norm.
Also, you asked what some potential concerns would be, so I listed some. Regardless of TRT or on a cycle, the labs that I listed are still a concern.