Single-family house from the 1970s with a currently cheap leasehold - sell or rent out?

Hello everyone, relatives of mine have a currently rented single-family home in a major Bavarian city, which is located on a property with leasehold. Here are the key data: Property with approx. 400 m² Land value approx. 750€/m² Term of leasehold construction: end of 2060s Current annual ground rent: approx. 250€ per year (last increased approx. 1 month ago, previously unchanged approx. 20 years; may be increased within the framework of the consumer price index) The house from the beginning of the 1970s and became part in 2023 and 2025 renovi