If you are referring to the two photos in your screen clips-
They are different images. Both are NEF -so not looking at Photoshop images. And their Basic Development adjustments are totally different.
Your Photoshop PSD (TIF) is possibly hiding in the stacked photo.
Sorry for my ignorance, but I am new. If I understand what you're telling me correctly I am unable to retain the same image quality when I move an image from Lightroom to photoshop?
Do you mean file format or image quality? . . . or both?
I think it is the file DSC_0731.NEF that you have sent to Photoshop, and the Photoshop PSD (or TIF) file you processed in Photoshop is possibly hidden in the Library because it is in a Group Stack.
If you click the mouse pointer on the small  badge on the preview thumbnail (Do this in Grid view), you will expand the stack so you see the Photoshop file. Keep an eye on the filename of the selected photo.
This badge indicates there are two images in this grouped stack.
If you do not want Lightroom to Stack the Photoshopped thumbnails automatically- open the Preferences dialog [Ctrl+, ] and in the [External Editing] tab- remove the check mark from the "Stack" option.
I am unable to retain the same image quality
Not true! Your photo in Photoshop is a newly created pixel image (PSD, TIF)- whereas in Lightroom you are looking at raw NEF files (as rendered by LR), but the quality you see will reflect any editing you do to the image.
And then there's the mysterious "!" icon i can see in the thumbnail for DSC_0731.NEF
Is that an issue for you?
DSC_0669.NEF is the original file I completed my edits on in LR. DSC_0731.NEF is the file that PS automatically sent to LR after I removed the lense flare in PS and saved the file as the original file type (.NEF).
I am simply wondering why the lighting is slightly off (DSC_0669.NEF is slightly darker), if it is the same file type, and I did not edit the lighting in PS?
Does PS automatically mess with the lighting after you save a file in PS from LR?
I welcome it with open arms because i dont even know what it is.
No issue encountered. I can view the file just fine. ☝️
Try saving it as a tiff as a test comparison, to make sure something about the NEF designation is throwing off LR.
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saved the file as the original file type (.NEF).
You cannot save as a proprietary raw from Photoshop! Photoshop cannot save an NEF type file.
Photoshop can only save- PSD TIF JPG PNG file-types that are 'Pixel' based RGB files.
Did you expand the Stack? I want to see the (PSD or TIF) file that is hidden in the 'Stacked' photo.
What method did you use to 'Open' the NEF file in Photoshop? Did you-
a) Select the file in Lightroom and from the menus [Edit in Photoshop] or the shortcut [Ctrl+E], or
b) Select the file in Lightroom and from the menus [Open as Smart Object in Photoshop], or
c) From a Finder/File Explorer window- 'Open' in Photoshop with ACR.
I need to know the details and exact steps of your workflow to understand more.
And then there's the mysterious "!" icon
This is not the 'missing photo' icon- this one indicates that metadata has changed in the file. Possibly because ACR (Adobe Camera Raw) somehow was used, and if so, how? and my reason for asking your exact workflow- a) b) c) ?
Back to your original question-
...669.NEF and ...731.NEF are both raw files from the camera that you are viewing -
Your screen-clips show- 669 has LR Develop adjustments made, and 731 does not. There has to be a 'difference' if you change the sliders of one file in the Basic panel.
I understand that you cannot save a NEF file in PS, however that NEF file was only visible in LR after i saved the NEF file as a TIF file in PS, BUT i am still trying to understand why there is a difference in the image appearrace.
I used option a) to edit the original NEF file in PS.
I did not mess with ACR.
Where is the TIF version? Can you post a screen-clip of the TIF in the Develop module?
In your screen clips of your original post you show two raw NEF files. The Develop sliders are different- they will show different.
A tip: In Preferences/Interface tab- remove the check tick from the box-
Then you will not see the confusion of Navigator window showing a different photo to the main window.