What do i do ?

Could you try something like sweet potato? Still soft but in finger form so he can grab it himself?

Toast and cucumber seem like quite challenging first finger foods

Everything you're describing, gagging, shoving in foods is all healthy normal learning for a baby and he should be exposed to it in order to safely learn to eat.

Read up on infant CPR to help your own nerves, giving him something like a chicken leg bone with just a little meat on it to help him learn to map his mouth, and check out baby lead weaning classes like solid starts or feeding littles.

You got this -

My girl was still eating purees at 8 months. She didn’t honestly start enjoying solids until closer to 10 months.

We eat a mix of both. Purees but also solids... IE pureed strawberries with a side of those silver dollar pancakes you get at the store or chicken strips with a side of pureed broccoli... sometimes its the reverse. You aren't doing anything wrong. I WILL say that the foods that are not safe to eat now, IE blueberries, grapes, etc... I will ABSOLUTELY puree them so the baby gets used to the flavor and serve it with a solid of some kind.

Him gagging is teaching him how NOT to choke. My daughter choked ONE time and ever since she now pinched things and breaks off a small piece to eat, it’s scary, but if he doesn’t get the opportunity to learn it’s just prolonging it. But really every baby is different, 8 months is still so little and you will know when he’s ready for more because HE will initiate it.

If you want to start off with things that start off solid and dissolve into spit that’s a good start, like a cracker or something. That way regardless to whether he gags or not it will eventually soften up enough for him to just swallow. And that will teach him too.

This is so real! Depending on your comfort- to get past this for me I gave my son the soft puffed snacks or half Cheerios so he started getting use to more textures and picking up food.

Short answer is yes, you would be delaying his development by continuing to spoon feed purees. He's got to learn to eat at some point! And actually the earlier the better.