ODF (file extension .odt) is LO native format. If you use it from the start, there is no problem.
But, if you try to manipulate an alien format document, e.g. DOCX, There is first a mandatory conversion to internal format. This conversion is approximative for two reasons:
- DOCX specification is not frrely and publicly availabe
Most knowledge about it results from retro-engineering documents. It is more or less guess game. Some DOCX features is still not thoroughly understood
- Word and Writer are not based on the same founding principles
There is a common intersection between both but some features exist in Word not in Writer and vice versa. DOCX being poorer in abstract typographical concepts, translation will use low-level directives to best approximte the intended appearance. This contributes to file size inflation and a formatting mess prohibiting document-wide automation
So, TDF recommends using its native format with its applications. This statement applies also to any provider and any program. LOL back!
If you have a storage problem (docx working better than odt), then your cloud service is not “neutral” regarding files. This is a shame.