I'm sorry to hear about your Dell laptop troubles. It can be frustrating when technology doesn't work as expected. If you don't mind me asking, what specific issues are you experiencing with your newer Dell laptop and Win-11?
As for using an older laptop with Win-10, it's important to make sure that your device is up-to-date with the latest software and security patches to ensure optimal performance. You may also want to consider upgrading your hardware if you find that your older laptop is not meeting your needs.
If you have any specific questions or concerns regarding your Dell laptops, feel free to share them here and I'll do my best to assist you.