If it’s purely about looks, they do make “dummy DIMMs” to make a four slot motherboard appear to look fully populated with just two actual sticks of RAM. 2x 32GB + 2x 0GB may be a better option than 4x 16GB to get 64GB.

Also, just in case it’s not clear 14th gen desktop is Raptor Lake refresh. Meteor lake is mobile only. The 14900k is pretty much just a 13900k with a new part number, so anything you see with the 13900k pretty much applies to the 14900k too.

Many of the 13th gen chips are rebadged 12th gen chips. As you probably have noticed, the i5-1335U is basically the same as the i7-1255U. These chips are nearly identical, the i7 can clock slightly faster, and has a slightly better iGPU, making it an all around better CPU, though the difference is negligible outside of benchmarks.

By the way, comparing laptop CPU’s benchmarks are tough since many laptops will thermally throttle and therefore are limited by their cooler. On top of that, these CPU’s also have a programmable TDP and it’s possible that the CPU has been limited. All other things equal, the i7 here will be slightly faster, but it’s possible if the laptop with the i5 has a better cooler or a higher power limit, it could actually be significantly faster than the i7.

One thing to also consider is that the 12400f is likely good enough for now. In a couple of years if it’s struggling a bit, you’d have a decent number of options for used LGA1700 CPU’s that would just drop right in.