Here's a couple deal-breakers against using OpenOffice, at least its current version (4.1.11):
• Though OpenOffice's Microsoft Word emulator can open .docx files, and you can edit them just fine, when it comes time to save your changes, you can't save the file in .docx format, since Microsoft has a copyright on the format--instead, OpenOffice can save files as .doc, but that format doesn't save some of the newer Microsoft Word formatting options you can choose for .docx files, but also even some simple formatting options, like the font, font size, etc. get changed when OpenOffice saves a .docx file as .doc--for instance, Palatino gets changed to Times New Roman, 10 point; Helvetica remains Helvetica, but it gets changed to 10 point; and who knows what else. This problem is at least partly a flaw specific to OpenOffice, because if you open the same .docx file in Microsoft Word, and save it as .doc format, the new file won't have any of these undesired font changes. And, even worse, if you save the document in OpenOffice's format (.odt), Word can't open the file.
• If you try to launch even the latest version (4.1.11) of Apache OpenOffice under macOS Big Sur (11), and maybe even Catalina (10.15), macOS will display an alert saying "OpenOffice.app cannot be opened because the developer cannot be verified". You can still open it by going into macOS's Security & Privacy prefpane immediately after trying to launch it, where there will be a button labeled "Open anyway", but this bogus--why isn't this developer verified with Apple yet? The download page for Apache OpenOffice (https://www.openoffice.org/download/index.html) has a button labeled "Important hints for OS X", but when you click on it, the only thing it says about an OS X version is "Coming soon". This has been its status since at least Oct 5 2021 when Apache OpenOffice 4.1.11 was released, half a year ago.