Official LineageOS 17.1 for Fairphone 3/Fairphone 3+

Since I got my Fairphone 2 weeks ago I struggle with very poor video during videocalls on WhatsApp and Signal. This was one of the reasons I switched to LineageOS but also on this ROM the problems are there.
On Whatsapp the receiver and myself see a very poor image, the skin quality is very bad and the image is pixelated.

On Signal the picture is even worse for the receiver. The pixels seem to swirl around on clothing. Also very pixelated picture. The weird thing is that I see myself clearly without distortion during the video call.

On Google Duo there are no problems however. Picture quality is clear for me and the receiver.

I am on Lineage-17.1-20210405-nightly.
Apps versions are:
Signal 5.5.5
Whatsapp 2.21.6.17
Google Duo 131.0.363693714.DR121_RC01

I tested on WiFi and Mobile data, there are no differences in quality. Speedtest results are:
4G 67,9 Mbps down and 21,2 Mbps up with a ping of 22ms.
Wifi 187 MBps down and 132 Mbps up with 9 ms ping.

Are there other people with the same issues?