If you’re going to replace the crossbowman with this unit, they should have the weakness they get from losing the crossbowman, and the strength they get from getting the unit. However, their positioning is still essentially the crossbowman, which is really meaningless.
It is a common practice in the AoE series to make something that is actually universal to be something unique to one or some civilizations. There is no need to argue against this.
I think the Chinese arquebusier and Royal Arquebusier are not bad. If you say the former should get a new name and the latter is not decent, then you can suggest to them specifically, rather than just trying to change a bunch of civilizations.
Divine Machine Battalion is actually a special division established by the dynasty to learn to use various gunpowder weapons (not just arquebus). Other troops almost only use traditional cold weapons, and this unit is responsible for ALL kinds of firearms.
In the thread of my suggestion for Asian civilizations, I made it a new special banner army card, consisting of the flame thrower and the three-eyed gunner (kind of musketeer-type consulate unit).
鳥銃
Google it yourself.
The rich Indian culture has more features that other cultures in the world have not. The Indian do not need this.
If Jingals were going to be introduced into the game, I would first make it a Chinese unit, as a kind of consulate unit from Chinese Isolationism or home city. Otherwise, let it become a mercenary. Comparing to your suggestion, no so-called “a substantial change” here.
Burmese, like Koreans and Vietnamese, can use units from their culture to make mercenaries, or make special native units for landmarks of King of the Hill mode. They definitely have more suitable units than Jingals.