Xert Player hangs during workout

Last night, whilst doing a workout, the web version of the player started pausing and falling significantly behind what was on my phone, to the point where it was 5 minutes or more behind.
I was using Xert for Android to play the workout, with an OTG Cable and Ant+ dongle.
My Laptop was running Zwift and Xert Workout Player web thing, and connected to the trainer via Bluetooth in the companion app.
I don’t know if this was related to the power on my phone, as having both the Zwift Companion and Xert apps running completely rinsed my battery.
Is there anything I can be doing to help this work better? Is there anything I can do to collect data to see if the problem is data from the phone or data to the laptop? Are there any traffic shaping rules I can apply to my router?