Matt Payne, I have one rental property, only because the idea of more landlording doesn't appeal to me personally at the moment, and have some money in notes / note fund, but obviously the value of those is correlated to real estate, too. Other than that (and my Beanie Babies collection, of course) most funds that I'm not using for land investing are in broad indexes in retirement accounts.
To the question you asked about whether it's stupid to go all-in on real estate -- you mention that you've focused on cash flowing rentals, so without having to count on appreciation or flipping properties to another buyer before the music stops, it seems like there are only so many things that could go wrong. I suppose if all your properties were in a single market, and the economy there took a significant hit, you could possibly face falling rents and/or higher vacancies, but if you have some cushion on the cash flow numbers, and/or are maybe diversified on the locations, it's hard for me to see where your major risk exposure would be, so if the returns work for your needs, I'd probably resist any temptation to go chase the next Tesla stock or Dogecoin, etc., as those things will be far more volatile.
You mention potentially funding an IRA. I wonder what your thoughts are on potentially investing in real estate through a self-directed retirement account? I suppose you effectively lose some tax advantage by holding real estate long-term in a retirement account (since there's no benefit from depreciation), but if the property does appreciate over time, it seems like holding it in a Roth account could be good -- i.e. no need to 1031 it when you sell, in order to avoid the tax hit, so the proceeds can be yours to do with as you like (in retirement, or up to the amount of your initial contributions to the Roth). Still trying to get a self-directed Roth 401k set up so I don't have direct personal experience here, but it seems appealing.