Original plan was to build 3-5 years down the road, but now with the lot fully paid off and significantly appreciated, I would like to use this equity to kickstart real estate investing into cash flowing properties.

The more items you can check off the stronger your position to get the contracts.  

I started off with a duplex in 2020 and now have a solid portfolio of rentals with my partner.

We suddenly had 2 homes and began exploring what our options were and that is when we discovered the intriguing world of REI and tapped into Bigger Pockets and Better Life Tribe, etc. to begin our education.In the time since his death and the probate process we have been paying his mortgage off and selling items from the home which we have been maintaining.

All of that is independent of one-off maintenance costs - for example, trimming my palms costs $100 a couple of times per year.

Networking and doing the legwork of marketing is really the only way you'll find off market deals. 

First off, congratulations on your condo's appreciation from $373k in 2018 to $450k now. 

That would be 1,200 listings right off the top. 

For the renovation i would call 3 contractors off of google and have them give you estimates for the renovation .

I'd start off with reading Avery Carl's book "Short-term rental, long-term wealth" if you haven't already.