Rent/Invest or Buy before Inheritance?

Hello! I am trying to make a rent or buy decision. I cannot make up my mind after countless hours of analyzing spreadsheets, so I am seeking general input.

I am 34 making about $52k per year. No debt. About $54k in retirement. I currently rent in Ohio at $865 per month, which is a hair less than the average rent in our city.

I am an only child and my parents are homeowners. They will bequeath the house to me when they pass (they are 67 now). My question is, is it a better long-term choice to just keep renting until i inherit or buy a cheap condo, keep it until they pass, and then sell it and move to the inherited house? It would currently be about $400 per month cheaper to rent, a difference I would invest. I know a lot of people say they will invest and don’t, but I would do automatic extra payroll contributions of the difference. I have controlled for rent increases and that difference going down over time, eventually with rent being more expensive.

I have done countless spreadsheets and the problem is that the decision has too many unpredictables. For example, if rent increases at 4% per year, better to rent, but if it’s 5% with some higher years, better to buy. If the HOA fee increases at 3% per year, better to buy, but if the HOA gets jacked up or if there is 10k of special assessments, maybe better to rent. Or if my investments do 8%, better to rent, but if 4% due to a bad economy, better to buy. Also, if my parents live to 75, better to rent. If 95, better to buy.

I have stress tested the crap out of it and am unsure what to do. Just too many unknown variables. Do any of you have general advice? I know 100% I want to live in my parents’ home, as it is where I grew up. I just don’t know what will gain me the most long-term wealth until then, renting or buying.

Thank you.