https://www.amazon.com/AMD-Ryzen-3200G-Unlocked-Processor/dp/B07STGHZK8/ref=mp_s_a_1_4?dchild=1&keywords=ryzen+3+3100&qid=1606223860&sr=8-4 and https://www.amazon.com/Intel-i3-9100F-Desktop-Processor-Graphics/dp/B07R7Q3JZH/ref=mp_s_a_1_1?dchild=1&keywords=intel+3+9100f&qid=1606223952&sr=8-1 if you go intel, https://www.amazon.com/GIGABYTE-H310M-2-0-LGA1151-Motherboard/dp/B07Q6264RX/ref=mp_s_a_1_1?dchild=1&keywords=gigabyte+b450m+ds3h+intel&qid=1606224007&sr=8-1 this a intel version of the other mb, and its easy to find 16gb ram for like 50$ but you can go 8gb, then upgrade later.
https://www.amazon.com/dp/B07HCT5GBD/ref=cm_sw_r_cp_apa_fabc_WCXASG2KCD1SAYG5WKF4?_encoding=UTF8&psc=1 https://www.amazon.com/dp/B07YP6CW8P?ref=ppx_pop_mob_ap_share https://www.amazon.com/dp/B07R7Q3JZH?ref=ppx_pop_mob_ap_share Im using this right now for 2 5070xts and a 2080, set them on 2 dish racks
I'd recommend the following to replace your Atom ITX board. If you need more ports you can either go with LSI 9207-8i HBA pcie card for 40-50 bucks or one of the those m2 to SATA adapters.