Your best bet is to copy the link out of your email and paste it into your web browser of choice. That way you have the web page open outside of your Gmail. It is asinine but not specific to Gmail. Other email apps do it as well. I’m sorry for your frustrations. I hope you’re able to successful unclutter your inbox.
Back in 2020, those of us who had been using the community document server were greeted with a notification stating that mobile editing was no longer supported and that we’d have to buy their commercial product.
Some folks quickly figured out a patch. Others, like myself, left with a bad taste in our mouths.
In the end, I can only speak for myself, but I chose LibreOffice and The Document Foundation for philosophical reasons.
https://github.com/nextcloud/documentserver_community/issues/94