why won’t my phone update to ios 14.6?

my iphone xs refuses to update to 14.6. it is currently at 14.4, and has been that way since i bought it secondhand back in january(thus i can’t delete any past updates as some people have mentioned, nothing shows up). it’s slowing down a ton and overheating and i’m hoping an update will help. when i try to update it in my settings, it just says “resume download” in the dark grey so i can’t tap it, and the top just says “estimated time remaining...” with no time. after that didn’t work i decided to try updating through itunes. it almost worked on my hp laptop i think but i didn’t have enough space so i went to my desktop. the desktop did not recognize my phone needed an update unlike my laptop, i plugged it in and said i trust it and no pop up appeared. i’m not sure what to do at this point.