On my acoustic I normally use just my index I pinch my thumb and index and use index nail downward and fleshy part up (bit like I do a uke) gets a soft sound that I like or I use the side of my thumb for really soft sound. Is this a bad habbit or is there truly no wrong way longs you're happy and it sounds ok. I cant do the pinch where your fingers make a kind of cross just pinch with my index and thumb in line and use my index alone or sometimes thumbnail on upstrokes if I want a louder sound but not normally. I am still mastering a pick I just dont like them much plus I love soft sounding stuff so should I stick with what I am doing. (I dont like picks because I played bass for 3 years and still do)

I have seen some people strum how I do with index nail and fleshy bit on way up but not many so im assuming its wrong. I also dont have much nails so it works for me and sounds soft.
funny thing I am old timer,good bass player plays the way you speak of ...that is a fact .........far as what you ask .......what ever you are doing seems little out of place to me ....not saying you are wrong ,just need to figure out what is going on with the sound ...stuming is very easy to do .......pick is easy I use light one ,you know the hard ones do not give sort of speak .the up and down part is what I mean......trust me when I play out and start jamming hard that light pick helps so much ....dose not,tear up your strings..plus the give and the bend of the pick is on spot ......and it is hard to play with out a pick playing a long song ,,,,free bird is one I do on my flat top .and trust me hard song to do unplugged sort of speak.........but I have pulled it off many times at the end of the night ,,lol....any hey try fiber type pick,,,,,,Dunlop I think is one ......plus they do not chip ..hope this helps chuck d
When I strum on the acoustic, I tend to pinch my thumb and index together as if I were holding a pick. That way my index nail will brush the strings on the way down, and my thumb nail on the way back up. That way I can vary the pressure applied to the strings, so the sound ranges from barely audible to full on in your face loud.

On the electric, I always use a pick (unless I'm finger picking)
I would think the only "wrong" way would be something that results in injury or damage to your guitar....
There are dozens of methods of getting sound out of your instrument; as long as the results are pleasing to you it's fine.
I know an awful lot of folkie players who never did anything other than a thumb-brush.