Featured picture in Twenty twenty theme

I’m utilizing Twenty twenty theme for my wordpress weblog.It is a new weblog.

1. When any individual visits my weblog from weblog url, posts look very odd with no featured picture & additional nothing like "Read more" seems in finish! It ends with […].
2. If i add a featured picture, then a really massive picture seems at starting of weblog publish(which i do not need, weblog publish is already full) together with different pics. What must be measurement of Featured pic(there isn’t a choice inside to alter the dimensions).
   3.Any individual advised me to alter theme to generatepress or others, saying you possibly can’t do a lot with this theme! Is putting of featured picture not attainable with twenty twenty theme?
   (This discussion board’s automated system has pressured me to make use of out there Tag "Theme-Twenty-twenty-one", not allowed to create precise tag" Theme-Twenty-twenty". Kindly bear with it.