Figured bass with brackets fail to export correctly to .musicxml

I am working on a project where I digitized figured bass from Bach chorales, and added some extra editorial figures underneath with brackets, like the first file I uploaded.

However, when I exported it as musicxml, it has two problems:
(1) Brackets are replaced with parenthesis
(2) All the figures (original and editorial) have parenthesis, so I cannot tell my editorial figures from the original ones anymore because of this (see the second file).

I am using MuseScore v.3.3.2.8849 on Windows 10.

Thanks for the help, and I can proceed with this project once it is fixed. :)

Best,
Yaolong