However while people in Windsor doesn't have the luxury of high paying jobs that GTA residents have, is it just a temporary fever of buying houses, or there is really something going on in this city ? 

Be prepared for a high rate/high fees 

Be mindful of high property taxes, HOA restrictions, and competition—networking with local investors and off-market deals can help.

By highlighting properties in high-demand areas like San Ysidro that are ripe for SB-9 developments, you'll attract savvy buyers and investors who are eager for strong returns.

Bonus Tip: If this quadruplex is out of state, I’d highly recommend building a reliable local team (cleaners, handymen, etc.) and maybe consider hiring a co-host or VA to help with day-to-day tasks, especially if you scale up. 

Take pics of all the junk (I mean high class heirlooms, which is what you'll say in the ad) and put it on craigslist asking for offers.

Investors aren’t avoiding the work, they’re just focusing on higher returns and leveraging their experience.That said, even the high-level investors we work with still BRRRR single-family homes, they’ve just added larger deals into the mix.

I am very concerned about so many investors being presented with questionable marketing practices and charging such high prices for information.

I highly recommend investing in a property management software, such as Hospitable, for syncing your calendar, automating messaging, and scheduling cleans, as well as a dynamic pricing tool, such as PriceLabs, for optimizing your pricing based on market demand, local events, and seasonality. 

I've walked their properties in-person, and their build quality is good.