@tomleslie I used Maple 2020.2 for 64bit Linux. I did that because one of the OP's very recent Questions was marked as Product=Maple 2020.
That code runs and takes 3.5sec to produce the animation and a separate and additional 45sec to render its first frame -- in a fresh GUI session with no prior output -- in Maple 2020.2 for 64bit Linux.
If I rerun without first removing prior output then it takes about 100sec for the additional rendering to appear, as measured by the time[real]() difference in a later, separate Exceution Group as well as my wristwatch. This also emits errors to the terminal from which I launched the GUI, including "java.lang.OutOfMemoryError: Java heap space" and "GC overhead limit exceeded". That's where I got my reported timing from.
If I rerun yet again it gets then it appears to stall, and the animation does not appear even after a very long amount of time. Eventually I have to kill the GUI process. The launching terminal is filled with repeated "Java heap space" messages.
If I do the whole experiment in Maple 2021.0 for 64bit Linux then it takes 3.8sec to construct and only an additional 9.4sec to render the first frame in a fresh session with no prior output. Upon repeat, with prior output present, it then takes 9.2sec for the first render.
The JRE bundled with Maple was updated for Maple 2021.0. The Maple Standard Java GUI performance in the this example is improved. But 9sec is still far from acceptable as time to render the first frame. And it gets worse still, as the grid size is increased past the quite modest [91,91].
So I stand by what I wrote before, about high resolution densityplot animations being an inferior methodology if the number of frames is not small.
Java memory performance and management might have improved in Maple 2021.0, but whether at 3 or 4 or 9 seconds for rendering it's still very poor for this modest resolution densityplot animation example. A good system would render the first frame in less than 1/10th of a second.
Tom, there is no need for aggressive statements of disbelief, just because someone else's experience differs from yours.