I'm a first-time real estate investor based in Germany, eager to learn and start my journey, of Italian citizenship.

However, since the new year, as we have started to receive client work, it has mostly been small remodel jobs.

I would start by getting a copy of the condo by-laws and rules and regs for the condo association.

some good examples here already but would add minimum loan size / property value I see a lot, unfortunately have to turn away a lot of people (esp. those just starting out) because their budget is too low and the property doesn't have enough value juice to make it worth it as a lender (plus more risky)

However, if you were to recommend a top 3 of learning material you wish you had when starting out, what would it be?

And a lot of start-up companies are migrating to this city as well, because of the efficient costs of living, the OSU campus that has thousands of students graduating and looking for jobs locally, and the availability of land.

If they are ghosting you, start by taking photos of everything and itemize their bill. 

You can use hard money and start buying properties then refi out of it.

The apps you're referring to are suited for hand-outs and entry level project starting points - not for official purposes - unless they can be imported into actual CAD software and manipulated (".dwg" files).

Start by reading the Ultimate Real Estate Investing Guide: https://www.biggerpockets.com/guides/ultimate-real-estate-investing-guide/introduction2.