Had studied civil engineering and worked at a few engineering firms before so I had a background but really wanted to be out and about working with my hands.

Quote from @Zhenyang Jin: I am a software engineer working in Bay Area.

An additional benefit of a detailed engineering-based Cost Segregation Study is that it can increase potential insurance premium savings as well as provide support for the property tax appeals process.

I have a degree in civil engineering and 15 years construction, site development, and short term rental experience and am looking to shift my focus/career towards real estate development, mainly raw land although if there were a house on the property could include fix and flip.I plan to purchase 50+ acres of raw land with 1000+ feet of road frontage, have it surveyed and split into separate 5+ acre parcels for re-listing.

Since graduating in 2021, I moved to Washington, DC to pursue a civil engineering career and am now feeling like I am in more of a position to start learning and pursuing real estate investing seriously.

I have moonlighted for several Architects and through hard work and good fortune stumbled on an opportunity to become an apprentice electrical engineer. 10 years later I am a senior engineer, together with my wife, have a decent portfolio of Real Estate.

You can read about the differences here: Cost Segregation Study Approaches ExplainedLet’s first start with what the approaches:Detailed Engineering Approach from Actual Cost RecordsDetailed Engineering Cost Estimate ApproachSurvey or Letter ApproachResidual Estimation ApproachSampling or Modeling Approach"Rule of Thumb" ApproachSo which of these approaches is required by the IRS?

Is it as simple as getting the site designed and engineered for the footprint, cleared and graded (all of which I am comfortable with), and then hiring a GC to build the building?

At this point regardless of price point a cost segregation should be a full engineered study through a reputable firm. 

You should connect with a structural engineer to take a look.