Hello @Matu25 ,
You are right that variation will fill your calendar more, as you can offer your property to larger markets.
There are two approaches for you to choose from:
Have two listings: one with two rooms and the other with three rooms. With this option, you can lock the third room in the two-room listing.
Have one listing (3 bedroom): set the price for three or four people and use the additional guest fee feature for any additional guest. In this option, you can't lock the third room because the listing is for three rooms. Here, there is a possibility that people will book for 3 or 4 people but still use all three rooms.
Each option has its benefits, and it depends on where your property is located, how much free time you have, and your management style.
Here is a question to ask yourself to help you figure out which option is better for you:
Which costs you more: an hour of cleaning or an hour of managing the dual listings?
I hope this helps.
Off-topic: I would like to suggest that you reconsider the property title. I'm not sure if the word "simple", the first word potential guests read, is the best choice for marketing reasons.