@sadmafioso worked through your guide and it works fine with Blynk 1.16.4 (not 1.16.5 as per your bug report).
The stream is also very responsive after the initial connection, perhaps 1 to 2s delay. With our current settings the stream stops quite frequently but generally it does restart automatically. Will try changing the settings to see if it will run better.
For IP cameras that only have mjpeg streams, and if you are not able / don't want to port forward, you can use OBS (Open Broadcaster Software) Studio (free) and YouTube Live to watch the stream via Blynk.
The stream is at least 30 seconds delayed with YouTube Live and you need to be able to run OBS. Even though OBS works across most platforms it does need a decent processor to encode the mjpeg stream to MP4 / H264.
We are now waiting for the proper H264 IP Camera we ordered from AliExpress, with 52% discount courtesy of the 1 day Global Shopping Festival on the 11th November.