Coming back from last winter vacation, I turned on again my desktop and the mobo was fried, I made a minor upgrade, keeping all the HW still working, HDDs, graphics card, case, etc and bought:
AsRock B450 Pro4 mobo
Ryzen 5 2600 CPU (back then the best value as performance/list price ratio in its market segment, even best value at the best Amazon price I found. BTW, unlike older AMD ones, this time the standard provided CPU cooler is quiet enough to not force me to buy a 3rd party one. It also helps that even with more than 80 tabs open in Firefox, most CPU cores stay under 10% power, so the fan can almost always run at minimum speed, the power leap from my old system has been huge even with a little more than entry level CPU).
16GB (2x8GB) ECC DDR4 (being an emergency partial upgrade with possible further ones, I started looking for 8GB in 2x4GB modules, but I quickly found that 4GB starting becoming obsolete, 16GB in 2x8GB just cost a very few euros more)
Cooler Master MWE 500W White PSU, as the old 400W one, besides offering little power margin if I later upgrade GPU and add other HW too, had an old mobo connector with just additional 4pin instead of 8pin, again barely enough for the current config, but possibly insufficient in case of future upgrades, moreover there was the possibility that the old one could be involved in the old mobo frying.
Outside nothing exciting to see, the old Enermax Pandora case, I even covered a passive cooling grille on the side with gray duck tape to force all air entering through fans with dust filters (I added two quiet 120mm ones to the one in the case standard equipment, all pumping air in, while the PSU fan pumps it out).