Which Format to Save Multiple RAW Image in to Retain RAW info?

Unlike Camera Raw and Lightroom, Photoshop is not a parametric editor; it only edits by directly editing and resaving pixels in a non-raw format. So, if there is even just one little edit that requires directly altering the pixels in Photoshop, then keeping the entire document in a camera raw format is off the table, it is not possible.

There is one way that might work: Instead of converting the raw/DNG images into a Photoshop document, see if it works to instead import the files (using File > Place Embedded) as raw/DNG Smart Object layers into a Photoshop document. Then make any Photoshop edits on other layers; for example, if you needed to use the Clone Stamp tool, set it to Sample All Layers and paint the edit on another layer over the Smart Object layer. The raw/DNG files stay that way and are not converted becuase they were imported as Smart Objects, and if you want to edit one further using raw controls, double-click it…it will open in Adobe Camera Raw.

What you would have is a document saved in Photoshop format that contains a mix of raw images preserved as Smart Object layers, and edits you added on Photoshop layers. Note that there is no way to take the combined raw + Photoshop edits and save those back out as a camera raw file.

That is because raw image data is like flour. You can bake flour into any dish you want, but doing any kind of baking at all will never let you store the result as just flour. Baking with flour in even the slightest way means it can no longer be raw flour, it’s impossible.

(Advanced) Using the Place Embedded command imports copies not connected to the originals. If you wanted to use less storage space (by not creating copies) and have any Camera Raw edits affect all linked uses of those raw files, you could instead use File > Place Linked to import them into a Photoshop document as linked, not embedded, raw Smart Objects. If this sounds like a more advanced and complicated workflow, it is, so you might not need it. I use this workflow because I like to be able to communicate raw edits two ways between raw files cataloged by Lightroom Classic and also used as linked Smart Objects in Photoshop. But this is a complicated way to work with a lot of strange details, and takes some practice.