With such abstract examples, you really don't help anyone. The rule of thumb of 30, sometimes even 40% of net household income refers to the incomes of the middle class. Different standards apply to low earners, who now often have to spend 50%, and for high earners it is indeed almost irrelevant because there is always enough left for basic needs. For everyone else, never more than 35-40%. It is, of course, possible to pay more, but then you can afford nothing besides the installment and basic needs and live in your own house but without vacations, without leisure activities, without the children's hobbies, etc. By the way, life has also become significantly more expensive compared to 2019.