And also it tells me to abort the ongoing installation process as it may harm my computer.
Windows 10
https://photos.app.goo.gl/AWf8V5hGMS69Hoe19
X-64 build
The default for new installations of Windows 10 is to prevent users from installing programs from anywhere except the Microsoft App Store. You can change this by clicking on Start Menu > Settings > Apps > Apps & Features and under Choose where to get apps change from Microsoft App Store only to Anywhere. Make sure you download LO from links provided by https://www.libreoffice.org/
As Microsoft has locked down your PC so heavily you might want to also look at General Installation Issues (Windows)
When you come to use LO you will probably need to change the anti-ransomware settings in your anti-virus to allow soffice.bin access to your documents and other folders. Cheers, Al
No no I don’t want to find a way to install it. I’m asking whether to trust it and install forcefully even if my Windows Defender says not to install it.
LibreOffice from the official download won’t harm your computer (but might reduce revenue for MS). I would strongly recommend installing the Stable version, currently 6.4.7, rather than the Fresh version which has new features but also possibly new bugs. I use the fresh versions sometimes, but for most work I use the stable version.
Underneath the download button on https://www.libreoffice.org/ is a small text link that says info, click on that and you can find SHA hashes. Check your download with with a suitable utility to make sure the hash value of the download matches that in the list. There is a built-in command line utility in Windows, there is a question on answers.microsoft that explains how to use it.
If you are still unsure you can purchase a 3rd party version of LO from the MS store, but what’s in it? Cheers, Al