Due to the popularity of the Dragon Ball FighterZ open beta, servers have been taking quite a beating. So much so that several problems have become apparent. Unfortunately, Bandai Namco has stated that these are not problems that can be fixed quickly. You can check out their full statement here:
Thank you for playing the Open Beta of Dragon Ball FighterZ and your invaluable feedback.
Our team is working hard on optimizing the Open Beta but ran into some issues that cannot be addressed in a short amount of time, so we are asking for your patience until the next server update.
The current Open Beta will remain online and available so that the players who can log in and play it, can keep doing so.
Please note, that if we cannot address the issues within a decent amount of time, we will consider extending the Open Beta of Dragon Ball FighterZ.
Thank you for your support and patience as we work towards an optimal gameplay experience.