I am beginner…?

Stop playing blitz if you want to improve.

The worst mistake you can do is feel you need to chase those blitz ratings back; it’ll be a waste of time and a disservice to yourself.

Start over with a clean slate and focus on 15/10 to give yourself time to think thru each move and blunder check.

You are Lower vs. a Beginner.

You are a Novice!

Beginner < Novice < Intermediate < Master....etc.

Improving Your Chess - Resources for Beginners and Beyond…

https://www.chess.com/blog/RussBell/improving-your-chess-resources-for-beginners-and-beyond

I have started playing 10 minute games, and you are awarded with so many more points than blitz! Does anyone know why this is?

It’s because you haven’t played rapid in a while.

They call it a glicko system where they factor uncertainties from when you weren’t playing routinely; you either gotten better or worser in that interim and hence you score more points initially but it stabilizes after 10-20 games.

Same thing is happening with me as I picked up the game again.

Cool. Does this mean that I could switch between rapid and blitz for increased elo?

The bigger jumps when you first start are a very clever way to help you level out at an accurate reflection of your ability much more quickly than if you have to walk there in small steady steps. If you imagine a master chess player (2500 rating) registering for the first time here and starting out at 1500 rating, she/he would have to play 125 wins just to get up to the rating where they'll be playing their peers. Similarly, a newbie who would win about half their games when playing at 600, if they start at 1200, is going to have to begin their chess career by losing 75 games, which would be really, really depressing.

By letting you jump ratings quite drastically at first, the system homes in, with big jumps followed by smaller ones, on your true rating. It is quite possible that your first win is a fluke, in which case you've jumped far too high, but your next will be a lose, and will jump you most of the way back again... the jumps get smaller as the likelihood of you being a long way from reality decreases.

Hello

Unlikely, because rapid and blitz are apples and oranges in that you need to gain the knowledge, tactics, technique and skill set first before you can start playing off intuition and time scrambles.

Which is why slower time controls are emphasized for beginners and improvement in general.