So the systems recommended to your father will funny enough barely be better than your config as well autocad need single core and that is about it. Both cpu's are pretty much around the same single core performance as the 3300x so waaay overspending there from the IT guy. Autocad does prefer quadro's but the gtx 2060ko is also a very nice competitor because of it being a cut down 2080 whilst basically performing like one in rendering. That and the p2200 kinda hovers around a gtx 1650s in terms of autocad performance it seems so maybe not really worth the massive price hike.
So my advice would be to go with your ryzen idea but get a gtx 2060ko as that card is cheaper than the quadro and will perform better. Or look for used last gen quadro's. A 2060ko is around a p3000 level of performance but in certain tasks gets close to a 4000 from what I can gather.
Ssd wise a regular old wd blue or mx500 sata drive will do as autocad isn't disk intensive. Psu wise anything from the list I will link that is b tier or better and 500w is plenty.
For a motherboard I would recommend any msi max b450 board or if almost no price difference a b550 board either will have support for ryzen 4000.