Some like flats, some don't. The majority opinion seems to be that you are silly to not clip in. Cross county folks seem to all like the clips, all mountain, enduro and gravity riders mostly seem to go with flats. Try both, use what you like when you like. In any case good pedals are key. If you are going to run flats run good ones, if you go with clips same applies. No one is paying you to ride a bike, might as will figure out what you like and go with that as opposed to what other people think you should do.

Yes, clipless is THE way to go.

I run Speedplay lollipops on my road bike and Shimano on my Mtn bike.

I tend to pronate and the lollipops allow lots of L-R movement. Mtn, it doesn't make as big a difference, at least in my case.

There's a learning curve and muscle memory for releasing from the pedal. Practice till it's second nature and eventually you will not even think about it.

I used to use Binda laminated straps on my old style clips because they didn't stretch. Pros used them so I tried it and until clipless, they were the answer.