How to add a picture

i need to use multiple images long the way, i need to upload them in a high resolution, but everytime i play the game the resolution is terrible, i tried like Sprite, UI image and UI Raw Image, but the quality is always pixelated, the image resolutions are 1983*1116, i need to work with the details of those pictures and when resized they just become pixelated, i've seen many other games puting pictures in the images and the resolution is good, you can see even the details, i leave some examples of what i've seen... and don't know how to do it maybe there are some options in the methods avobe mentioned that i'm not paying attention, i need to understand where is my mistake.

https://ibb.co/9ptPdhR https://ibb.co/B2qtwk7 https://ibb.co/vQ0DHS8 https://ibb.co/MkYy0P2

i need the pictures to lool like this, where you can notice details