Should have been embedded in my text but if I failed at mobile this is the generation I had. It looks like there's a newer one as well. https://www.amazon.com/dp/0321492668/ref=cm_sw_r_cp_apa_i_u2SNCb0DNJY9B
I liked the Practice of System and Network Administration by Tom Limoncelli et al. when I was starting out. Some of the specifics may be dated but the concepts are good.
Edit: there's apparently a 3rd edition here
If you want to beef up your infrastructure knowledge specifically around maintaining servers, this is the book my systems administration class used in college. Check to make sure it's been updated to cover infrastructure as a service if you feel inclined, but it has really good coverage on what RAID is, how and when to do backups, etc. It also provides suggestions on general IT infrastructure stuff you might not be aware of.
Well I'll be the first one to give you generic information that you could have found with the search function.
You just do the needful.
Good screwdriver set.
A network tone tester in case you need to map out your network and document everything. Also functions as a basic cable tester.
A punch down tool.
An ethernet crimper.
A quick cable stripper.
A usb hard drive dock.
Your necessities may vary, this applies to more of a one-man shop, and there's plenty of other things you'll want to get that I don't have listed here depending on your job.
I dunno how much you should get paid.
There's no such thing as an "ESXi book" any more than there is a book about the windows calculator. It's a fairly small part of the vmware vsphere environment.
You can start with this platform independent book:
Thomas Limoncelli's book is pretty highly regarded: https://toptalkedbooks.com/amzn/0321492668
I personally created this Poster a while back... feel free to use it: https://www.reddit.com/r/computertechs/comments/1qhcsa/poster_troubleshooting_in_black_and_white/