Thank you.
But I ended up getting it before.
I installed ej2-locale with npm and them just updated my tsconfig to allow json with:
"resolveJsonModule": true,
And then in my main ts file, the one with all the base imports, I just:
Worked like a charm
import { L10n, setCulture } from '@syncfusion/ej2-base';
import { pt } from '@syncfusion/ej2-locale/src/pt.json';
setCulture('pt');
L10n.load({
'pt': pt
});