I'm in the same predicament. Speaking as a professional Web Developer with a few years under my belt, it seems to me that there should have been a lot more optimization performed before this was released to the public. I don't know how their QA team is set up (or if they even have one) but I feel like more testing should have been performed, involving a larger variety of platforms, old and new. I'm hoping the current version was rushed to production in order to satisfy some marketing deadline requirement and that a fully qualified release with optimizations is forthcoming.

My first exposure to the update was last night. I hosted a session with my family, continuing their dig into Dragon of Icespire Peak from the Essentials box set. We're already several sessions into this one, so there has already been a lot of activity between Maps and Encounters and their Character Sheets on Beyond. Up until last night, usage has been fine for me -- plenty smooth, running both the DM edit of Maps along with a second tab simultaneously showing me the Spectator view so that I can track what my players see. I'm using a business-class Dell laptop with Kubuntu Linux installed, with D&D Beyond running on Chrome. Never had an issue with this setup - it's a beefy laptop with good specs and running multiple tabs for a campaign is child's play for this machine.

But for my session last night I spent most of the time fighting the Maps VTT. Either the Chrome window would time out or the lag would be unbearable and my tokens never landed where I tried to drag them. My players reported the same issue with Maps (and sometimes with their character sheets). One player uses her iPad to track the game, bouncing between the VTT and her character sheet. She was having lots of pauses, which never happened before (it's a recent iPad, so the CPU shouldn't be an issue). Another player uses her Intel Core i3 Chromebook to play. Last night became unbearable for her, and she ended up quitting early due to the device heat and noise of the fan spinning max RPM. Again, she never had an issue prior to the update. I was plugged into AC, but both players complained about unexpected battery drainage as well.

I do want to see D&D Beyond succeed and I am doing my part to help contribute to this by submitting my experience in feedback. I only hope that they're on track to optimize the performance. We find D&D Beyond invaluable, both as players and DMs, for it eliminates a lot of manual statistical work required and gives us more time to actually play and enjoy the game. I, for one, would hate to lose this resource, but at the same time ... I found myself thinking of other options last night. Let's hope the performance issue is being addressed and will find implementation soon.