Owner GC, how difficult is it?

I am currently a renter and have always wanted to build my own home for many reasons. I live in a place that I can pull an owner permit, I have pretty good construction knowledge having worked for HVAC and Plumbing contractors for the past 6 years (mostly managing work, little hands on). I’d likely build slab on grade as that is standard where I live, 1,000-1,200 sqft, self perform as much as possible and even try to use reclaimed materials where I can to save on cost. If I only have enough cash to purchase the land outright and plan to pay as I go for the build over say 18-24 months what issues should I plan to run into specifically related to a slow build? Has anyone financed their land and paid cash for upfront building costs and worked on a pay as you build basis from there? All advice is appreciated.