firstly, you’re looking at investing all wrong. Diversified investing means owning all different classes of assets - cash, stock/bonds, real estate and other appreciables. So great, you own stocks/funds, what else?
No doubt returns have been great the past 3-4 years, but a downturn can easily wipe that out, something you’re not accounting for, especially when stating things like 10% return is reasonable (this is not the average person’s return given most people are in the market due to their 401k and don’t know a thing about investing). A 3-4 year recession plus the 2-5 years it takes a portfolio to recover sets you back completely while you could have another asset class continuing to appreciate - as long as the recession isn’t caused by a housing collapse, yet even so, this is why I say buy multi family.
If you don’t have a family, or don’t have a big family, no need for a SFH as young person. Buy a duplex or triplex, when he market crashes and people lose their homes, they still need a place to live and you’ll have supply to offer.