X470 and B450 are chipsets, and don't specifically affect VRMs. However, X470 is the more expensive chipset that offers SLI support, while B450 does not, so it is likely that X470 motherboards will be more expensive and may have better VRM solutions because they are competing in a higher price bracket. With that said, if you don't need SLI then a B450 board is just fine.
I just got an Asrock Fatality B450 ITX motherboard and am running a 2700X with it. A big reason I wanted this particular board was because it has Intel LAN, Intel WiFI, Intel Bluetooth, and the Realtek ALC1220 sound chip. I also don't want SLI, so there was no point in getting an X470 board for me.
The weaknesses of this particular board are the VRMs (ITX in general have weaker VRM due to smaller space for packaging everything) as well as only two RAM slots. Neither was an issue for my use case, and I am very happy with the motherboard.
As far as your choices go, I would look at the various components and features and decide what you like best. Also look at the BIOS and see if it has the features you want. My previous computer was an Intel Z77 based build, also using an Asrock motherboard. That computer was still running strong when I got the itch to upgrade (it was the 7 year itch as well) so I have had a couple good experiences with Asrock motherboards. I really don't think you can go wrong with most motherboards. There's a youtube guy who does very in depth critiques of motherboard power circuitry, buildzoid I think, so you might see if he has any reviews of the boards you are thinking of. He tends to be pretty critical IMO, with an eye towards overclocking and heavy power use, so keep that in mind. But if he says something is good, it very likely is (at least in the power delivery aspect).
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