12700K is a good top end option IMO from using it since they dropped last year.
DDR5 has a "tax" though and doesn't offer much benefit other than novelty and expense. The performance just isn't there to justify the extra $100 for 32GB nor the $100 MOBO price increase. Sure, it might be a nice to have when they engineer it to actually provide some edge over DDR4 but, it's just not there yet.
https://www.nowinstock.net/computers/memory/ - this is helpful in reducing the costs if you stick with DDR5 though.
Combo deals with NE aren't what they used to be and might add up $30 off but, they make up the difference somewhere else in pricing these days.
I usually come up with an idea on the final solution and then find sellers that are whores and sell each part on the cheap. Mid tower's are still a 24" x 24" setup and for what you're putting into it are way too much case but, the options for say an mATX board are still quite limited if you want the perks of more lanes to use for peripherals over the B660 or lower tiers.
For the drives though you would get more performance using dual NVME's over the 2.5" option for the same price. That's why I mentioned the SN770's above. If you were building more of a NAS into the case I would recommend WD Red's @ 8TB or higher.
LC IMO is the same as yours when it comes to electrical + liquid not being the best idea. I leave my machine on 24/7 because it's my router as well so, building with that in mind makes things a priority for uptime.
When you take the NE deal and split it among different merchants it's 837 vs 797 so, $40 difference for the "deal". However when you factor in DDR5 tax due to them not offering a DDR4 bundle using similar parts it's going to be less.
https://pcpartpicker.com/products/memory/#t=14&Z=32768002&L=30,180&sort=price&page=1&S=3600,6600 - 3600mhz / $105 vs $200
https://pcpartpicker.com/product/X6...a1700-motherboard-mag-z690-tomahawk-wifi-ddr4 - $259.99 - same price either 4 or 5
CPU stays the same price though if you have a MC nearby or someone that's close by to one you can knock off $30
https://www.microcenter.com/product...ga-1700-boxed-processor-heatsink-not-included
They also have MOBO / 12700K combos for ~$550 depending on the board / DDR version
Micro Center - Computers and Electronics - Thousands of products to buy: desktops, laptops, monitors, build your own PC parts, upgrades, digital imaging, printing supplies, portable devices, audio equipment, software, video games, movies, tech books, plus repair service, store hours, directions...
www.microcenter.com
They even have a MOBO/CPU/EVO 1TB for $$805
https://www.microcenter.com/product...sung-870-evo-1tb-25-ssd,-computer-build-combo
Anyway... just some things to consider before locking things down. The name of the game is to do it as cheap and effectively as possible compared to a pre-built. When I rebuilt my server the effective cost increase over the 8700K I was running was within $200 even with upgrades with selling the old version in mind which made it a no brainer. I picked up PCIE 3 >> 5 and the potential DDR5 option until the market went wonky on prices. Then diffing deeper into the specs made it less of a great idea worth spending the extra "tax" on. I'm finding myself being a bit more tame when it comes to making changes to it unlike the prior version where it seemed every couple of months I was tweaking things or swapping the case for something different for better thermals or more PCI slots on the back or compressing things into a mATX case w/ enough drive bays for the NAS drives. Maybe I just got it out of my system in a been there, done that sort of philosophy.