Thanks for reaching out isj1,
It sounds like you're having some trouble with your battery performance. We can help.
A great place to start would be to check which apps are using the most power by tapping Settings > Battery. This could potentially narrow down the cause of the drain. Additionally, you could check the next screen, Battery Health & Charging to see details of your battery health overall.
Like all batteries, the iPhone battery is consumable and will eventually need to be replaced. An iPhone battery is expected to last a minimum of 500 charge cycles before the battery health drops to 80%. Once it drops below 80%, replacement is needed.
Your usage will determine how fast replacement is needed, but you can check out these articles to learn more about your battery and how to get the most out of it:
If you are visiting an Apple Store, they can also run a diagnostic to test your device as well.
Hope that helps.
Take care.