iPhone 11 unable to download and install iOS update from 15.5 due to error

I’m having issues downloading and installing iOS 26.7 or even the iOS 27 (downloaded that but it wasn’t installing) so i deleted it and trying the 26.7.

I use an iPhone 11 and I’m still on the iOS 15.5

I have been postponing any software updates because i didn’t have enough storage on my device. Even though I have over 100GB left in the cloud that’s not being much help. I have now deleted most things from my phone because my apps now ask for an updated version, and these updated versions need a newer iOS to run on, understandably.

So how do I successfully download and install the update? I have cleared up space, when it gets to 2 minutes left for the download I get an error message and it has to restart.

I think because the iOS i have is so old, the phone is finding it difficult to make that link. So is there a way I can download an iOS that’s not this new one? One closer to 15.5 but is still supported. I think that’s the solution here but these older software options aren’t showing in my settings.

This storage situation is quite frustrating and it would be good if our iCloud space actually mattered in the grand scheme of things.