I totally don't mind investing in systems and know-how, and really liked the presentations and reasoning of their model, but the guy who called me on the phone was from the Negation School of salesmanship or something, wasting far more time than is polite in an effort to prove to me that I'm NOT a good fit!

To properly renew a lease with a tenant, several tasks SHOULD be done:1) Evaluate the property to make sure tenant is taking care of it and you want them to stay.2) Do a market analysis of rental rates.3) Determine target rental increase amount4) We present all this to the tenant, as we assume they're looking at rental rates on Zillow, etc.5) We then ask the tenant what adjustment they think is fair and then negotiate rent amount and lease term (we always try to go for 2 years).6) New lease sent electronically to sign.All of this takes time, hence a Renewal Fee.

Also, our proximity to D.C. is causing double-digit appreciation, and still a very competitive market. 

Sounds like you were actually getting a deal before at $60/year but it wasn't digital..

The contracts I am being presented by co-brokes are sometimes riddled with errors and mistakes.

(We're both digital nomads, so we get to live and work from anywhere!)

And the only family I still had there was my dad who isn't very present (to say the least).

Cold calling has been unfruitful as well, so I'll focus on digital leads for my next attempt. 

Do you have a desk set up for professionals traveling with partners and/or digital nomads?

Without knowing exact numbers it is hard to have a firm opinion so I will present some items for you to think about. - upon sale, the property tax will be increased to be based off current market value (~1.1% of current value).