I have rental properties in Ireland and Germany, my own house in Germany and my shares are deliberately weighted away from these 2 countries.
I have no real clue about which company is the next big thing, so I invest passively in a MSCI ACWI ETF, a bundle of shares in app 2,400 companies spread across 23 industrialised nations and 23 emerging markets but 90% weighted towards the industrialised countries, which in turn are mostly weighted towards companies based in the United States but most/all large US companies derive profits globally so you are not overly exposed to the US economy itself.
It works for me like this as World ETFs barely factor the Irish economy in at all and even Germany is only 3% or something like that.
I wonder have you considered teaming up with any friends or family to buy property? I am testing the water with my immediate family and one or two of my friends. I currently have a house which I am "house hacking" (I don't really like that term, rent-a-room scheme is more accurate). I want to invest in another property and I am currently saving and exploring options.
I looked into releasing equity from my current house but AIB said NOPE. (They would do it for refurbishing the current house but not for investing in a new property). Someone on here very recently suggested I look at Pepper Finance so I will be exploring that option very soon. In the mean time I will be saving for a 20% deposit and finding ways to increase my income.
I would not buy property with family and friends. Nothing tests a relationship like money. Even if everyone is in agreement when the investment is made, circumstances change. One party might want to sell, or be impacted by the investment in getting another mortgage, or other life events may mean not everyone is aligned. Will excess income be distributed or used to pay down a mortgage quicker? Who decides when to sell? If further investment is required, what if one party cant afford the additional investment?
Asset diversification is less important than matching assets and liabilities.
e.g. don't have income and expenses in different currencies.