

From the blog-
Pursuant to Section 7 of AGPLv3, the copyright holder is expressly entitled to impose additional conditions. In the case of ONLYOFFICE, such conditions include, in particular:
- the obligation to retain the original product logo (Section 7(b));
- the denial of any rights to use the copyright holder’s trademarks (Section 7(e)).
Such additions to the License were implemented on May 25, 2021, and can be found at line 655 of the License.
ie. You’re not allowed to rebrand the software as something else and additionally, not allowed to use their trademarks without their consent - they’re trying to turn something agpl into ‘shared source’ proprietary software.

Not really, unless you’re employed by one of the big tech companies contributing to it, your pull requests are piped directly to the shredder, same with xorg, gnome, etc.
You can fork them, but why bother when it’s a mess designed to ensure the employment of its contributors, ‘WallyWare’ if you will.