The tips of my shimpaku juniper bonsai recently turned brown. The branches have also turned brown/white.

I removed the dead branches but did not cut anything that was green. I suspect it could be overwatering and there might be some root rot. Any suggestions on how I could get my tree back to a healthy condition?

I'm considering taking it to a bonsai place so that I can get someone to repot and clean out the roots since I don't feel comfortable doing something like that.