Bro here 14700k is 100 dollar more than 13700k. Also u dont need gen 5, gen 4 is sufficient. Not much application can leverage that much bandwith, not to mention the availability of gen 5 ssd is still limited and still high in price. If your on a budget get z690, z790 is waste of money. That if still available tho.
I say go for DDR5. In case you want to upgrade you don’t need to buy new set of rams. Also, people will look for DDR 5 for their new rig, selling them will likely much easier than having DDR4. I say this because I could not sell my old sticks after major upgrade LOL.