Ring door bell burning out tranformer

I had a ring door bell2 for several years. Hardwired , battery always at 100%. No issues. All of a sudden battery started discharging. Transformer was bad. Installed new transformer . It burned out as well. Called electrician . He installed new transformer . That burned out . Told me the ring door bell is defective. Keeps burning out transformers. Ring sent me a new doorbell 3. Issue is the battery is not at 100%. Slowly going down. Found out it doesn’t keep battery charged. Why did the 2 have no issues and the new 3 doesn’t charge the battery????? This is a flaw. Don’t understand . You would think it would be better.