MC version:1.19.2
placebo: 7.1.5
apotheosis: 6.1.2
I test the critical damage with dummmmy, jei, and apotheosis. It seems critical mechanic is not as what I recognized.
Conclusion,
0, Base critical damage is 0.
1, There is a not low base critical chance for weapon with only critical damage, and if the critical chance enough, base damage will always be multiplied.
2, Critical chance above like 30% seems a trigger to another critical mechanic, deal (1+ "critical damage +%") * 150% damage.
Because of the key words of weapons and gems are basically the same descriptions for same affixes, I just wonder if the mechanic is working as intended.

Critical hits interact as you would expect unless you are jumping (invoking a vanilla crit)

i.e. you have X% chance to deal +Y% damage, unless you are doing a jump crit, in which case you deal the formula you described above (X% chance to deal 150% * Y% damage)

@Shadows-of-Fire I didn't jump, but I get 70% critical chance and +0% critical damage, it behaved the same with jump hit. Deal 150% damage. You can try with sword like this,
here is the result

Yes, you have a base critical damage of 150% (representing the jump crit damage)

@Shadows-of-Fire And the formula I described above is the behavior from my test, not as you told me.
There are two condition,
1, If I have low critical chance or 0 chance, I may deal X * (1+Y% critical damage) damage.
2, If I have high critical chance, like 70%, I may deal normal X * (1+Y% critical damage) or critical X * (1+Y% critical damage) * 150% damage.

If I don't have +crit chance affix, it can still be mutipilied . Test with this sword.

And if my critical chance is low, like 25%, I can't deal 150% damage.

Is your base critical chance value set to 1.5? You can check it with /attribute
Old versions of the mod would incorrectly set the base value.

@Shadows-of-Fire That's it, it's 1.0, I don't know this until now. Thanks. But if there's a wiki, I may solve it myself and not bother you.

Wait this is crit damage, and this is chance,

Yes, old versions had them swapped. You can fix them with the command by changing the base values.

And what should I do next, the crit chance is 1.5, set to 1.0?

OK this works, thanks.