My current that I built in 2014 is a bit long in the tooth. I’ve used a i7-4790K CPU with a GTX 1070 GPU and 16 gigs of DDR3 2400 ram, and an Asus 1080p display. My hope is to assemble a new rig that will enable me to run Prepar3d v5 and MSFS 2020 with mostly ultra settings and to move up to a larger 1440p or 4K display. 
To date, I have acquired a Fractal Meshify case with plenty of airflow, a Ryzen 5800X CPU, a 1000 watt PSU, and 32 gigs of GSkill Ripkaws V DDR4 3600 ram for this build. Good start. 
My question today is what motherboard will best serve my needs for a flight sim rig, the more mainstream B550 chip based Mobos, or the more enthusiast oriented Mobos based on the AMD X570 chip? The sales rep at my local Microcenter recommended the Asus Rox Strix X570 Gaming E board over the Asus Rog Strix B550 product. His pitch focused on the more robust feature set of X570 - PCI 4 support for the GPU and two M2 SSD sockets, 8 SATA 6 ports, many USB 3.2 ports, and plenty of bandwidth to spare on these features. The B550 board would likely meet most of my needs, with PCI 4 support for a 3080 or 3090 GPU, sufficient PCI 4 bandwidth for a fast M2 NVME drive in slot 1, along with 6 SATA 6 ports and a good number of gen 3.1 USB ports. I would lose a couple SATA ports if I used the  M 2 slot 2 socket, but I can’t imagine that my storage needs would not be met with the B550 configuration. 
Yes, the X570 feature set is nice, but has downsides. It has been stated in reviews that  m2 SSDs provide only marginal improvements for gaming, so is M2 SSD support that relevant?The X570 board costs about $100 more than the B550 boar so is it cost effective? Also, the  570 chip runs on twice the wattage and generates a fair amount of heat that must be dispersed by a small chipset fan. I’ve seen plenty of comments that these chipset fans are noisy and perhaps prone to fail. I certainly don’t need more heat or the problems reported on the PCH fans, if this is a valid criticism. 
Could those familiar with these Mobos provide me their views on what is the better choice in this flight sim oriented build?

Thanks, Rich

B550, the reason is because the next AMD socket would be AM5. The difference between B550 and X570 is the PCI gen 4 slots for NVME SSD. With B550 you can only have 1 PCI-E Gen 4 for your NVME while X570, you can have 2 PCI-E gen 4 NVME.

I had to make the same choice a year ago with my 5800x. Save your money for the next platform and 1x PCI-E gen 4 for NVME is more than enough IMO. I got myself Strix B550-F Wi-Fi version.

Thanks TrentXWB for your reply. That is how I am leaning, since I can’t imagine I would need two M2 drives to accomplish the storage I need. One such socket and the SATA SSDs should be adequate.  Save the money and avoid the x570 heat and chipset fan. 
How hot is your rig running with the 5800x. I plan to deal with it with ample airflow from the Meshify case, several 140 mm case fans and a Deep Rock 4 Pro CPU cooler. 

I am using Arctic Liquid Freezer 240 also with Meshify case but I live in a tropical place, ambient temp of 30c so it is on the hotter side. I use Noctua AF12-25 for the AIO as well, I also use curve optimiser. On idle it is around 40c and on load it is around 75-80c.