acer nitro 5 battery

Hello, today my new laptop arrived (Acer Nitro 5 an515-45) also my first laptop (I used only desktop before) and it's battery is kinda weird? I mean it spikes from 4-5 hours to 2-3 hours, sometimes it shows 5 hours remaining then 2 minutes later me not doing anything it shows 2 hours remaining...

I bought an acer nitro 5 (Ryzen 5 4600H, gtx 1650) five months ago, it was perfect, and when I use power saver mode the battery shows 8 hours remaining, and it last about 6 to 7 hours browsing the web, I really like it, and it remains this performance 5 months, and I care so much about it, when...