You should be good with those. Usually it's best to match brands/models, however, I looked at the specs and both of these are 144Hz with 1ms MPRT and the same size/resolution. There may be color/contrast differences you'll need to adjust via each monitor's OSD menu. FreeSync/Gsync work the same on AMD. Gsync has software in the driver package to mate it with the monitor but the technology was developed by AMD and is open source, meaning other companies can brand it different. All you do is enable FreeSync on one, GSync on the other if the driver doesn't automatically turn it on.
A hint would be to run the 20.8.3 driver for that card, the newer drivers aren't so hot with the 5000 series cards. Link: AMD Radeon™ RX 5600 XT Previous Drivers | AMD
Scroll down to the Windows 10 x64 20.8.3 driver and download it prior to installing the card. Stay offline and disable automatic driver updates in the Radeon software to prevent it from changing on you. If you currently have a video driver installed, remove it with DDU in safe mode first. Link: Display Driver Uninstaller Download version 18.0.3.5 (guru3d.com)
"It worked before you broke it!"
