So pretty much I have set the Sharpness Enchantment Level to 7 and a trader is giving it for 10.
I set it through apotheosis enchantments.cfg

(Here are the in-game photos)

Minecraft : 1.18.2
Forge : 40.1.84
Apotheosis : 5.7.6
Placebo : 6.6.6

Yes, that's expected. These trades are statically defined via data files https://github.com/Shadows-of-Fire/Apotheosis/tree/1.19/src/main/resources/data/apotheosis/wanderer_trades

So if I make a datapack with the same path but just change the nbt: of the item in the output will that work?

For example the bonesplitter.json has this "nbt": "{Enchantments:[{lvl:10s,id:\"minecraft:sharpness\"},{lvl:1s,id:\"minecraft:mending\"},{lvl:5s,id:\"apotheosis:hell_infusion\"},{lvl:2s,id:\"apotheosis:capturing\"},{lvl:5s,id:\"minecraft:looting\"},{lvl:3s,id:\"minecraft:unbreaking\"}],display:{Name:\u0027{\"translate\":\"name.apotheosis.merch_axe2\"}\u0027},Damage:0}"
if I just change the numbers in the lvl is it going to be ok or can it cause problems?

That will work