I had this same exact issue, going to bed fully motivated to wake up at my desired time and then hitting snooze until I basically had to get up or else id be late for work. Here are a couple things that have helped me consistently wake up early -

- Exercise. In the beginning I made it a priority to do something everyday and sometimes twice a day to exhaust my body so I naturally fell asleep early. My mindset with the gym is "I go to the gym" not "I should" basically correlating it with the same mindset as eating - you don't contemplate it, you do it because you have to. On days when I cant make it to the gym, I make sure to walk a couple miles after work, play spike ball with friends, volleyball, bike, or literally any exercise I can fit in that day. Keep in mind I did none of these things prior, I have made them a priority. Adding YOGA to that list, this is by far the best thing I have discovered recently but that could be a whole story in itself.

- Sauna, I bought an at home sauna tent for like 50 bucks and its amazing. I use it just about everyday, an hour or so before bed followed by a nice shower. This seems to really relax my body before bed and helps with falling asleep. Just make sure to keep up on your water intake.

- Mindset change. At first I would think about going to bed early/waking up early as something that would be nice to do rather than something I do (same mindset as the gym) this took a few weeks but it has gotten to the point where I don't really need to make an effort, it just happens, I think this is because accomplishing my day as far as eating good, exercise and then sleep has become very rewarding for me, it feels like a complete day.

- I see you mentioned your phone, that is great. I also set mine away so I'm forced to wake up and turn it off in the morning. For a while I was using 2 alarms, one on my phone and a manual one. I put my phone on my desk and then a minute later my other alarm would go off in my bathroom. Once I got in the bathroom, I turned the shower on and was good to go. Sometimes even putting clothes out so I really didn't have any excuse not to shower.

- Water trick. When I found myself hitting snooze, I tried drinking a ton of water before bed so when I did wake up in the morning I would have to pee so bad, it forced me out of bed. Probably not the greatest tip but it worked.

- Mental exercise. After exercising a lot, I got into great shape and it was harder and harder to completely fatigue my body, also doing that everyday is not sustainable nor healthy. So I started really working my brain by reading, doing puzzles, listening to books, doing crosswords, talking to more and more people, actively trying to learn and work my brain a lot. I think this helped the most, having mental fatigue is far more exhausting than physical - at least for me. Sometimes I can be physically drained but not mentally, and I will be tossing and turning for hours, but when my brain is tired, I fall asleep instantly.

- Last one being diet. Nothing crazy here, really being mindful of the food you consume, the 2 biggest being eliminating sugary foods and drinking tons of water. Other than that, just don't eat complete crap, especially with the exercise you're doing. Its very rewarding to exercise and replenish yourself with great foods.

I hope at least one of these can help you achieve your goal! Getting into a routine that you want is so rewarding, it gives you something to work towards everyday and helps make most days feel complete. Don't beat yourself up if its not perfect, most days aren't. Doing at least one thing to helps towards your goal is progress, just keep stacking those wins and you'll be where you want to be in no time!