Well not sure what you're thinking about with automation?
If you're thinking input into Excel or Sheets, then yes...I would expect everyone does this today.
If you're thinking you type in "Riverside Apartments" value on ChatGPT, I don't know that that ever works. Not all data is public? For example how many units in your comparable are classic vs Platinum. Do they have stainless or white appliances. Are all the AC units new/er or are they all on their last leg. What is unit mix of 1/2/3 bedrooms? Is it class A/B/C, B+ or B-? Does it have carports? If so are they charging rent for those? Do you have inhouse construction department to reno units, or are you hiring outside contractors? What new apartments are permitted around it...or 1/2 way thru construction, but not on the market.
How do you become an expert or master it.....probably like any other skill...practice. Wasn't there a book something about 10,000hrs of practice or maybe it was a chapter in a book. I would say that is about right.
And in the end, as @Arn Cenedella wrote, it is as much art as science...so even the best killer spreadsheet only takes you so far. Your competition will probably use better or worse assumptions. Interest rates and cap rates change, competition changes, your PM ends up being horrible, lots of variables.
Just to throw you a monkey wrench, in your killer spreadsheet does it include the credit score, income, and employer of every resident? How about that of your competitors? What if it is 90% occupied with employees of one company. Everything looks great and a year later that employer goes out of business or lays everyone off? Would people say your underwriting was good or bad?