focus is your problem, and maybe dss (i get the same problem trying to stack my own, takes some practice to get it working in dss, i stick with pixinsight mostly. Take notes and work out the software process.
There are NO optimal settings, 4 sec is usable, maybe not to get photos like someone with years of experience and $20k+ worth of gear but you can get nebulosity and certainly more than your eyes can see looking up.
Work on getting good focus, try autofocus off the moon to get you started, stars will still be distorted away from the middle of the frame (using a slower aperture can improve this). Get a good set of shots (dozen lights and dozen darks, raw not jpg) that are in focus even if its boring part of the sky (no matter where you point the camera there are always going to be stars to align and stack with. now play with DSS, take notes, work out what settings will work to use your test set. Its a tedious boring process trying to get going in AP, nothing to do with buying better gear or just pushing a button. Experiment and learn and take notes.
once you get the process of taking photos and processing them then its just a matter of where in the sky to point
its all good. its interesting to plate solve a random shot and find you've captured a cluster, galaxy, nebula in the shot and then learn to reprocess to try to bring them out better.