I wouldn't buy a separate residence for this - the regulatory environment in general is highly biased against that use case, so it comes with an unacceptably large legal risk IMO.

Instead, I'd suggest buying a primary residence that is a duplex or is larger than you need, and subletting out the extra room(s) or other half of the unit. Your financial commitment is much less (just the difference between purchase prices of larger vs smaller houses), financing via mortgages is much more reasonable, and legal statutes that cover this use case tend to be more favorable to you.