a point of improvement but overall I would use Libreoffice and OnlyOffice (preferred) gladly.

Let's start with LibreOffice.

When I try to insert a citation in LibreOffice Writer, Zotero gets stuck. To reproduce:

Given that EndNote doesn't work with Google Docs at all, that wouldn't make a whole lot of sense. Zotero's Word and LibreOffice plugins aren't affected by this bug.

version => 5.0.95.1, platform => Win32, oscpu => Windows NT 10.0; WOW64, locale => de, appName => Zotero, appVersion => 5.0.95.1, extensions => Zotero LibreOffice Integration (5.0.25.SA.5.0.95.1, exte

I can't add the LibreOffice plugin. I found the possibility to do it but it seems wrong

version => 5.0.95.3, platform => MacIntel, oscpu => Intel Mac OS X 10.9, locale => en-US, appName => Zotero, appVersion => 5.0.95.3, extensions => Zutilo Utility for Zotero (3.8.0, extension), Zotero

What version of Java is selected in the Advanced pane of the LibreOffice preferences?

extension), Jasminum (0.1.0, extension), Zotero LibreOffice Integration (5.0.25.SA.5.0.95.3, extension), Zotero Word for Mac Integration (5.0.32.SA.5.0.95.3, extension), Better BibTex for Zotero (5.2

version => 5.0.95, platform => Linux x86_64, oscpu => Linux x86_64, locale => pt-PT, appName => Zotero, appVersion => 5.0.95, extensions => Zotero LibreOffice Integration (5.0.25.SA.5.0.95, extension)

version => 5.0.93, platform => Linux x86_64, oscpu => Linux x86_64, locale => en-US, appName => Zotero, appVersion => 5.0.93, extensions => Zotero LibreOffice Integration (5.0.25.SA.5.0.93, extension)

Just in case I downloaded as you instructed and tried that version in LibreOffice. I added it by selecting "Add" and browsing directly to the Oracle package. It then appeared as: Oracle Corporation 1

When I tried the oracle-java15-jre that installed with LibreOffice, the result is the same.

Those aren't relevant. This has nothing to do with Zotero — it's entirely a problem in LibreOffice with your system Java configuration.

I uninstalled LibreOffice and Zotero and reinstalled everything again. For Zotero I downloaded directly and followed the instructions here: https://www.zotero.org/support/installation. Here is the err

I have submitted a bug to LibreOffice.

LibreOffice Integration’.

This is a problem with LibreOffice not being able to use your JRE and not specific to Zotero. You should try different versions of Java. Make sure LibreOffice sees them and they are selected when test

I cannot get Zotero to work with Libreoffice since upgrading to Linux Mint 20.1 Ulyssa. I have followed the instructions here to no avail.

Usually this is due to LO profile corruption. Trying closing LO and deleting the 'user' folder in your LibreOffice profile folder.