Hi @questMate
Is there still a possibility to check my appointments in the calendar without a look-ahead time?
Yes, we can. For your meetings created long time ago, we can achieve it. But during the test, I found some limitations.
Most of the steps are similar, we just need to add one more loop to create break meeting for each. For flow details:

It creates all break meetings successfully. However, I found some potential problems need to inform you in advance. I named the new break meeting as ’15-mins break new’. As you can see, the first flow I tested yesterday created a break meeting at 5:30-5:45pm 3/22. Today, the secondary flow creates meeting at the same time. It means meeting conflict. However, the calendar can’t find this conflict and allow flow to create it.
For example, if you have already booked meeting1 at 9-10AM, and meeting2 at 10-11AM. The secondary flow will create break meeting at 10-10:15AM. It will overlap with your meeting2. Thus, I recommend you can using flow to create break meeting for incoming meeting instead of meetings booked long time ago. There is no any other better way to calculate the time between two adjacent meetings. If you can confirm you don’t such kind of consecutive meetings, you can try this flow.

Hope the content may help you.
Thanks
Anna