You can play with the numbers, ultimately it remains a trade-off between two good, practical solutions.
But reverse the consideration about the net return:
Let's assume you get a home loan at 2% and you want to achieve a net return of 4% on the condominium (due to higher risk and additional effort). With the numbers as above:
12 * €500 net return => €6,000 p.a.
Break-even value of the condominium => €6,000 * 1/0.04 => €150,000.
That means the net return decreases when the value of the apartment is above €150,000 (if the rent cannot be increased accordingly). The question now is what buyers are actually willing to pay within, for example, 3 months for the condominium. According to the calculation, you would have to seriously reconsider or raise the rent at the latest at €175,000. If you are actually offered €200,000, the net return on the capital employed drops to 3%, barely more than what the bank wants from you – then the interest rate swap is no longer worthwhile and that is ultimately what it is all about.
In addition...
If you can achieve a sales price of €175,000, you still need €95,000, which at 2% loan costs is about €159 monthly burden WITHOUT repayment. Amortization calculators are available everywhere on the internet; you can quickly figure out what remains with bearable burden.
At €200,000 you only need €70,000 and then you pay that off even faster... and become completely debt-free.
I would therefore only hold the apartment if it is in a corresponding location in a major city or an area experiencing population growth, where you can calculate with additional above-average appreciation. Otherwise, the time effort and risk do not pay off – and that exists with individual properties.
Best regards Dirk Grafe