Help needed! I'm sure I've doing something wrong in Rising Star for 15 months, can't figure out what it is.

It was roughly about August 2021, when I tried Rising star. I had heard about it 3 months earlier, but never really got around to starting. Honestly, I think it was the graphics, they didn't really appeal to me.
In September I finally committed to the game and validated my account. I also had done some quest and transferred some funds to buy my first pack. It's contents were R87 Stacy,34 Drew,i39 Cheap Electric Violin. It helped me to start doing other missions and customise my performer.

Since then it feels like I've been doing the same cycle for over a year. Click a button to start a mission, collect XP and Starbits. Save the starbits untill I can buy another pack and then do more missions. I'm currently level 48 with 61 unique cards and ranked #3820.

I have the feeling that I am underperforming at the moment and should be:

• At a higher level than 48 after 15 months
• Have a larger collection then 61 unique cards
• Have more gameplay than just doing missions/training

Is there anything obvious that you have been doing that I should implement into my gameplay? Any advice is greatly appreciated.