Closing - please decide if you wish to file a bug report for “slow and laggy”, of if you simply want support help to troubleshoot it.
The support gurus in our support venues https://community.ubuntu.com/t/finding-help/7121 are awaiting your support question.
Unfortunately, this is not the right place for support. Sorry.
Since Gnome 3.30 is not yet in the Ubuntu repositories, it is unsupported. If you wish to install unsupported software, you are on your own. We wish you good fortune with your endeavour.
Were you offering to package Gnome 3.30 for Ubuntu, or offering useful testing feedback to developers, or coordinating efforts for development, those would be appropriate activities for here.