Some LOs don't like the stage between puree and regular foods so mashing or cutting small might not be the right approach for your LO. How about trying large, adult finger sized pieces of fruit, veg, toast, meat, rather than mashed? Larger pieces are easier to pick up and easier to grasp, think of half the food being held in a fist grip whilst the other half pokes out the top to be eaten, this way LO has more control of getting it to his mouth.
It also helps to see you eating exactly the same thing so he gets the idea of what to do and hears your 'yum' sounds so knows it's good. But otherwise don't panic, just keep offering. You might find it easier to offer some thing suitable from the family meal rather than preparing lots of different things just for him to then feel your efforts are wasted. I made changes to how I cooked the family meal, chopped veg larger, cooked without salt, things like that.
There are lots of ideas listed here
Finger Foods for Young Babies (6-9 months)BLW recipesYou could just start with steamed carrot batons or oven baked sweet potato wedges/fingers, fingers of toast or pitta/naan bread etc. Also don't be worried about having no teeth, LOs gums are amazingly hard and they can gum away at just about anything. Mine never had puree at all, at 6 months he happily gummed and sucked away on a piece of roast beef along with Yorkshire pudding, roast potatoes and veg etc. During teething many LOs even like something hard to gnaw on as it can offer relief, mine liked hard sugar free biscuits and bread sticks when teething.
hth