What should I be testing between R7800 and Wrt32x

The Linksys WRT currently has no perspective for WPA3 support (driver code support from vendor missing and unlikely to come) and some IoT Wifi devices have issues.
Depends on how far you take if abroad and which region device version you have: Its hard coded Wifi region code makes it impossible to adapt to regions other than the region which is hard coded into the Wifi chip. I guess it works, but either will violate local regulations or will be TX-power-limited when falling back to world region mode.

Yet though w32x feels to have great Wifi distance coverage in the region where it is meant to be used.

The WRT also has the dual partition scheme: When you mess up one partition, don’t worry: simply turn it off/on 3x and it will boot flawlessly into the second independent firmware partition.