TrueType fonts slow down LibreOffice

Hello. I found that LibreOffice is so slow and its CPU range is so high if use TrueType fonts like source code pro built in LibreOffice or OpenSans typing Chinese in kubuntu19.10 and Windows 10. I tried to turn OpenGL on and off, it is not work. Is this a bug or some of my setting is wrong?
I am using Libreoffice
Due to my mother langurage is not English, maybe what I am saying here is not so clear enough and may have a lot of grammar problems.

How can you tell the problem stems from using TrueType fonts? Have you tried using only OpenType fonts or only Type1 fonts? Or are you saying the LO-included TrueType fonts are the cause (but how and why)?

My reasons about why I thought TrueType fonts cause this problem because “Nato Sans CJK HK” ,“SourceHanSansCN” and “Noto Serif CJK SC” will not make this problem. These are OpenType fonts.

I can’t found a Chinese font which is Type1 fonts.

Also, I use firefox send(Dropbox and Google’s service are not available in China mainland) send the file that may cause problem(OpenSans.odt) and which is not(Noto Sans CJK HK.odt)

I set it to 100 download or 7 days to get outdated, which is the maximum of Firefox Send

I myself cannot reproduce this problem with TrueType fonts but I’m not writing in Chinese either. Possibly bigger minds than mine like @RGB-es (the font expert) or @mikekaganski (all-around LO genius) could offer an opinion…? In the meantime, avoid using the TrueType fonts and use Noto Sans and Source Pro Sans OpenType if possible.

Yes, Writing in English would not reproduce this problem. Seems this would only happen when I was using Chinese. Therefore I offered that link which can reproduce that problem. Whatever, should I take this as a bug and report it?

Yes. I would. and create an account if you don’t already have one. 我给你加油

Thanks, I submitted on