Laser printer streaky output

Toner? How many sheets do you think you have printed since installing the cart?

What I found with my HP laser is when the toner got low I’d get similar but a quick shake of the cart would fix it for a while.

So try taking the cart out and rotate it around the long axis a few times and see if that helps. (edited)

The good news is that looks like a toner issue rather than an engine issue. A gentle side to side tipping of the toner cart might sort it - or just replace the toner cart. Dell stopped making printers many years ago - I would put my money on it being the toner cart. (note that it can't accurately report on the toner status - especially a 3rd party one!) (edited)

the toner cartridge needs replacing

In case no one's mentioned it yet
Toner

Thanks, all.

i try not to print anything with lots of background shading like the one in the picture as that takes a lot of ink to colour in the shading.

if i print out a voucher, i tend to use pdf to blank out the colour areas so that it doesn't use too much ink when i print, so i only print what is needed and ignore all the peripherals. (edited)

Successfully fixed with a new toner cartridge; thanks again to all who replied.