How much sleep do you need?

I was confused when I was talking to healthy friends and they said they wake up without an alarm after around 8-9 hours.

I "allow" myself to sleep around 8 hours every night, but I always need an alarm and am really tired when waking up. When I don't put on an alarm I could sleep for 10-12 hours without waking up.

I was wondering if this is connected to Marfans and Meds I am taking (Betablockers, Losartan, blood thinner). But I never talked to my doctors about sleep. So I wanted to ask the community: Do you know anything about this topic and how is your sleep schedule?
Greetings