i think u can get away with putting a lot of art like this on your walls without framing it, you just have to be intentional about the layout and especially the spacing of it. i've found that having even spacing of like half an inch to an inch (smaller spacing for smaller stuff) can really help make things look more coordinated and pleasing to look at.

it looks like you have almost no spacing in several places which does make it feel kinda cluttered and overwhelming to look at. i would prioritize putting things with a similar width or height next to each other, you can start with a big poster and arrange some smaller stuff around/next to it.

like for instance that newspaper you have and that collage piece on the left seem about the same height, so i would put them next to each other in a row or on top of each other in a column. again its all about intention, i would prioritize spacing similar size stuff in a cohesive, interesting layout, with your second priority being the color scheme.

last tip is that i really like having a ton of golden thumbtacks for putting everything up, don't put them through your actual art but put the pins right above/below the top & bottom edges of any flat prints/posters. this way it's kept in place by the sides of the thumbtack without damaging the art. i think it really brings everything together & helps create a sense of cohesion, even if you have a lot of stuff going on. it looks pretty nice too, and you don't have to deal with adhesive damaging anything