There isn't a command like that, but if you go to your world save folder then:

datapacks > Fast Villager Curing > data > fast_villager_curing > functions

then open cure.mcfunction with a text editor you can change this line to set the amount of ticks for curing:

execute as @e[​scores={zombie_villager_conversion_time=2..}] run data merge entity @s {ConversionTime:???}

replace the ??? with the amount of ticks you want (60 ticks = 1 second, the vanilla amount is a random amount between 3600 and 6000 ticks).

No, but here's a Github link for my datapacks before updated to 1.18, the faster villager curing functions were in "Mob Control": link. For 1.18 I split the pack into different packs to make it modular.

Or you can edit the this pack to make it compatible by renaming "zombie_villager_conversion_time" to something 16 characters long. It's found in "setup" and "second" in the folder: "Fast Villager Curing\data\fast_villager_curing\functions"