So, I'm still leaning toward the i5-13600K. It's only about $10 more than the i7-12700K, although about $45 more than the i7-12700KF.
For me, the biggest unknown is the motherboard.
I've looked VERY hard at DDR5 boards, but for almost all of the ones I've considered, it will add $200-$300 more between the increased cost of the board and buying DDR5 RAM.
Over the past ~30 years, I've built (for myself or others) maybe a dozen PCs. In almost every case, I went with a mid-grade ASUS board because of quality and feature set. That seems to no longer be the case. (except in the high-end ROG lines) Their boards in the $250-$400 range all have pretty bad reviews. (unless I'm missing something major)
I've spent a couple of days reading reviews from some of the bigger tech sites, perused the reviews and ratings at Newegg, Amazon, and B&H.
To my great surprise, it seems like MSI (in spite of a few bad reviews about broken parts in sealed boxes) seems to have taken the lead.
My board REQUIREMENTS are:
Less than $400,
no fewer than 2 M.2 sockets,
6 or more SATA3 connections,
no fewer than 6 USB Type A ports on the rear IO, (don't care if they include 2.0, 3.0, 3.1 v.1, 3.1 v.2, etc...most of my stuff won't know the difference

)
BIOS Flashback (I don't have a 12th gen CPU to use to update the BIOS)
After all that, the following are the ones with the highest reviews that meet my requirements:
MSI Pro Z790-A DDR4 (4.855 )
MSI Pro Z690-A DDR4 (4.733 )
MSI MPG Z690 EDGE WIFI DDR4 (4.60)
MSI Z790 MAG Tomahawk DDR4 (4.504)
MSI Z690 MAG Tomahawk DDR4 (4.567)
GIGABYTE Z790 AORUS ELITE AX-DDR4 (4.350)
ASUS ROG Strix Z690-A Gaming WiFi D4 (4.333)
(ratings are averaged from the 3 sites listed above)
Common parts, regardless of CPU/Motherboard are:
I already have:
be quiet! Dark Base Pro 900 case (lots of room for everything)
Seasonic Focus + 750 watt PSU
EVGA RTX3070 FTW3
32 GB (2x16) Corsair Vengance LPX DDR3600 RAM (not actually in any of the QVL for any board, but SUPPOSDED to be compatible with the DDR4 boards)
WD SN770 2TB SSD
HP EX950 1TB SSD
Samsung DVD burner (I have 2, but nowadays, only need one...rarely, so COULD just not put it in)
Haven't bought YET, but on the list:
WD SA520 SSD 1TB (open to a different SSD)
Arctic Cooling liquid Freezer II 280mm (probably ARGB, maybe not) (I could POSSIBLY fit a 360mm or 420mm cooler if I forego the DVD burner)
will probably add:
Thermalright CPU Contact Bracket
GPU Brace
I've looked hard at DDR5 boards (and did the review averaging) and the ones that meet my needs will add at least $200-$300 to the build costs. (higher board prices plus purchase of 32GB of DDR5 RAM)
This is kind of strange territory for me. I've never even considered MSI for a build before. Their documentation (as compared to ASUS or ASRock) really sucks...but their boards seem decent.
Opinions? Advice?
Thanks.