Replaced Genuine Apple Battery shows sudden drops in Battery Percentage

My iPhone 12 battery was at 73% and the battery settings indicated me to replace it. Upon arriving at an Apple Authorized Service Provider, the professional explained me that I should replace my battery. I agreed and made an advance payment. The professional said that there was only one iPhone 12 battery remaining with them and urged me to submit my phone on the same day. I agreed . I received my phone the next day in the evening. After initial check, i noticed that my battery showed maximum capacity at 100% battery health. And 'Genuine Apple Part' appeared in the About section. I was convinced. I signed and received my phone. But, after i got home and plugged in my phone on charger, i noticed that my phone heated up very much.( This was very intense and I had not experienced this before with my device ). Further, i noticed that after charging my phone to 100% and unplugging, my charge dropped very fast. This change is new to me. Because, when I bought my phone 2 years back, I experienced only gradual drops in my battery percentage ( charge ) when using it. But, now even after replacing my battery, I experience sudden battery percentage drops very fast. When i asked the Apple Authorized Service Provider where I replaced my battery about this issue, they said that it was okay and my battery replacement was covered under 90 days warranty. I doubt that my iPhone 12 was replaced with a refurbished battery. Is this possible? Can I claim warranty or ask for another battery replacement or even refund of my money, if this problem persists within the said 90 days of warranty ?

I will further update this thread if I notice any improvements or problems....

Cheers ✌🏻