Sure, diversifying excess profits into RE is not a terrible idea, but what most people don’t realise and fail to take into account, is the overhead costs.
You don’t want your RE deteriorating to oblivion, do you? Land on the other hand, has zero maintenance, but cannot offer any immediate income - whilst waiting for it to appreciate in value. Definitely less hassle though.
TLDR: Land, not RE.
I always considered land to be real estate, regardless of what structures may be on it. Real estate consists of land and any existing structures.
Land is an appreciating asset while generally structures are a depreciating asset, precisely because of the maintenance you mentioned. This is why I consider condominiums to be a sucker's bet while bare land is an excellent investment. As Mark Twain said, "they don't make it anymore".
Bare land can offer immediate income. Arable land can be leased or sharecropped to farmers. Bush lots can be logged or used to harvest firewood (preferably on a sharecrop basis).
By avoiding any construction you can avoid tax increases. You just have to play it smart.
I pay less than $2000 per year in taxes for 400 acres and a 25 acre private lake in prime Muskoka cottage country because I live within the confines of the local municipal zoning bylaws. I'm allowed a trailer for habitation between May 15 and Oct 15. I got a used 37' trailer with two tipouts, bathtub and 3 bunk guest bedroom for less than $2000. The lake is so pure you can drink from it and I intend to keep it that way. I bought a pedal boat and plan to get a canoe. No motors will be allowed. My land is a nature preserve.
It's also increasing in value. There's no reason why you can't invest in land and enjoy it.