The Inspiron 15 3505 shines with low noise levels, two drive slots, and a moderate price. The installed Ryzen 5 APU does not reach its full performance potential. The battery life is poor.
https://www.notebookcheck.net/Dell-Inspiron-15-3505-in-review-Quiet-affordable-office-laptop.612574.0.html
Did you figure out what's wrong with your test sample yet?
Try Win + S > 'See which apps are affecting your battery life'.
Should be >95% for "Edge".
If true, manually switch 'on' all energy-saving policies in Edge admx.
Also, your readings from charger brick are too high (appears like decade-old laptop).
1 year working very well. Then, the keys started falling one by one from the keyboard, and the screen now shows a green bar at the bottom. I have been the most careful person with it. Does not worth it.