Case in point, home repair and reno costs are up since 2019.

That's my opinion.Another good one is AppFolio, but this is very costly.

The owner would cover the cost during vacancies and within the first week or so of a new tenancy if needed as a courtesy.

How much is the average cost for the upgrade? 

Low Repair Costs: With only $2,500 needed for repairs, the investment required minimal additional funds.

Unless you are an attorney practicing real estate in the state of the subject property, the chances of reaching a wrong conclusion are too great and the consequences too costly.  

Is it because the cost of their service is fixed and therefore they try to do as little as possible, or is it something else?

The buyer agreed to a purchase price and all fees/costs.

Many clients from Canada also boast that pricier neighborhoods in the U.S. for example Miami, are only a fraction of the cost of properties in Canada, so their ROI is much higher. 

It's in a city (outside the USA in Mexico) that has seen major growth the last 3-5 years and has great prospects to continue growing thanks to nearshoring and high cost of living across the border in the USA.I spoke to an architect and it looks like a 4-unit building can be built on there.