If you're buying a 5080 (or even a 5070, to be honest) you might as well just get the 7800X3D or 9800X3D.
They are expensive, but MMOs tend to like these CPUs and you're already forking out on the GPU, so there's not much point saving the money if you can afford to buy one.
If you did want to keep costs down, a £130 motherboard like Gigabyte's B650 Eagle is going to be near indistinguishable from a say.. £200 B850 board, but I'd just get PCI-E 5.0 to avoid any possible headaches in the future with upgrades.
If you really like the shinies, have a look at Antec's C5 ARGB, it includes 7x 120mm ARGB fans which makes it decent value. The C8 Curve looks better, but doesn't have any fans. Fishbowl cases are not to my taste, hence Lian Li's 216.
Note that if you get a case with a lot of included RGB/ARGB fans and then fit a 360mm AIO for aesthetics, it can cause cabling problems (if you have to strip out what is already done from the factory) and something I'd personally want to avoid messing with.