What bit should I use to drill a two inch hole in a solid concrete wall?
Hire a core driller.   Trust me and do it.  You will regret doing this yourself and the cost will seem like nothing in comparison to your struggles with drilling a hole that size in solid concrete.

probably cost you 200 bucks.

You can rent one from a tool rental company, or even from home depot....  https://www.homedepot.com/tool-truck-rental/Small-Core-Drill/3510639/index.html

But trust me, as someone who has do this five or six times a year, just hire someone for this job.  By the time I calculate all the time and cost of renting a drill rig and diamond bit and figuring out how to use it and then returning it .... its never cheaper.