It seems like you can move to the next or previous file with tab + up/down arrow keys.

I just found out by mashing all the buttons I could think of. :-)

This is not exactly it. What I meant was, something what IrfanView does: when you open an image (or any file the program can read), you can press a button to open the (alphabetically?) next or previous image in the same folder.

Looks like Preview only has this, when you select all files and open them (Cmd+O). Wish it was like IrfanView.

I’m confused here , so like if you’re in a folder with a file selected and hit the space bar , does pressing the arrow keys not preview the next file for you ?

It does not

Try up/down arrows, not left/right.

Nope, does not work.

To scan the files in your folder like that you can use quicklook. Just press space to open the first one and use the arrows to navigate. Another super power of macOS.