Oh, I get it now! Currently, when dragging or zooming in and out, the ground, weeds, and rabbits are being redrawn. Of course, for the weeds, the browser is using a cache of about a minute, but due to network latency, this part might be even more noticeable to you. I personally really like Firefox as a browser, but as you mentioned, I'm quite disappointed to see that its rendering performance is relatively poor. I'm also a bit worried about whether it will continue to receive good updates. (A long time ago, I even bought a smartphone that came with Firefox OS. lol)

I'll definitely need to take a proper look at the solutions you mentioned this time. I also remember Konva being very useful in the past. Thank you for the detailed and kind response.