What Settings can I use for my pictures to stay bright as they are when I capture before saving

What troubleshooting have you done so far?

The photo enhancing algorithm is built into your iPhone's chip. Your device automatically applies the filter to each and every photo you take. The culprit has a name: Deep Fusion. It could be the problem in your case.
Please go to Settings, select Photos, and disable View Full HDR. Take a new photo and check the results.
Please, follow the steps above and update me on the results.

First things first, try turning off the Full HDR option. Go to Settings, select Photos, and disable View Full HDR. Take a new photo and check the results. Hopefully, you’ll notice some improvements.

Please try this:
Use the Key Photo Option
Take a photo with Live Photo on.
Then navigate to Photos.
Select your live photo and edit it using the Key Photo option.
Basically, you’ll change the focus to a different point within the live photo. If you do that, iOS won’t auto-enhance the frame that you selected. That’s another way to access the original, unedited version of a photo.

I would recommend you to.

In most of latest iphones

In Photos, tap a photo or video thumbnail to view it in full screen.
Tap Edit, then swipe left under the photo to view the effects you can edit such as Exposure, Brilliance, Highlights, and Shadows.
Tap the effect you want to edit, then drag the slider to make precise adjustments.

You can edit your photos to look brighter by doing these steps:

1. In Photos, tap a photo or video thumbnail to view it in full screen.
2. Tap Edit, then swipe left under the photo to view the effects you can edit such
   as Exposure, Brilliance, Highlights, and Shadows.
3. Tap the effect you want to edit, then drag the slider to make precise adjustments.

Try these and let me know if you need anything else