Constant buffering of 4K Videos on iPad

Hi,

My setup:
Synology NAS → Ethernet to Wifi Router → Wifi to iPad Air 2022 (NFS protocol used)

Lately (past 3 months) Infuse has been extremely slow in loading movies and has serious buffering issues with movies (especially 4K ones). The playback always stops approximately every 3 minutes to buffer. After 20 seconds playback continues until it stops again to buffer after 3 minutes. This keeps on going on and makes Infuse pretty much useless at this point.

I have run a speedtest for 10 minutes and get constant 150 Mbps, which should be more than enough for 4K. Thus I assume the issues is somewhere with Infuse or the iPad. I’ve tried playing with the Streaming Cache options, sadly to no avail.
Has anybody had similar issues or any ideas how to solve the issue?

Thanks

Can you provide a screen cap of the graph from the speed test?

Sure:

If you let the test complete to 100% are there any more down spikes that go below 120?

Seems it drops a few times, however not every 3 minutes as in the case of actually playing the video: