Talk calls with high CPU on clients

I have a Nextcloud instance on a VPS with a Almalinux distribution. Everything is up-to-date. Every computer that connects to a Talk call sees its CPU climbing at 60-100% with the browser window running Talk being around 40-50%. This is very high compared to Teams or Zoom. Is there anything I can modify or optimize to solve that?
Thank you

In fact, the GPU is even higher with 96-100% during the call with a Microsoft Surface 7.
I have checked all logs of the server and of my PCs without finding anything obvious. It is the same whatever the browser. I haven’t checked yet the brand new Windows client.
Any idea what to search for and what to optimize?