It still needs the extra Netty library, but now different openHAB versions use different Netty lib versions it is far easier to just install the telstick binding which will take care of the Netty libs so the single jar works. You can download the jars from the mvn/maven website, or install them with the console using the info from this post making sure you only use a single version of Netty on your system. The mqtt binding also uses different parts of the Netty libs.
That link will be the fixed version and should work on all 3.x versions of the core.
Try using the autofps.mjpeg stream as it updates every 8 seconds when there is no movement, then will change to every second when motion is detected. Tablets will handle it fine and there are widgets for OH3 that can make setting it up easy.
Another way would be to use snapshots.mjpeg and set the pollTime to 3 seconds and the stream will be a picture change every 3 seconds.
Yet another way is to use an Image item or oh-image card that gets fed the ipcamera.jpg url and set to update every 3 seconds.
All three of these ways will stop the image data going through the event bus and result in less load.