[queensoft]

I used jDownloader2 for many years, never had this problem.
Windows 10 Pro x64, i7 7700k, 16 gb ram, ssd for windows, wd blue 1 tb for download
300 mbps download internbet connection, TP Link Archer C2 router (cannot test dircet connection, cable too short).
Speedtest.net is OK, 300 mbps donwload, 150 mbps upload
Everything is updated.
Tried with both firewalls (router, windows) on and off.
Tried with advanced setting youtube ratebypassenabled on and off.
Tried router restart, change IP.
Tried several chunks/downloads combinations.

Tried 4K video download = lightning fast, 7-8 mbps, download a short video in 4-5 seconds.
Soke too soon !
First 2 test videos downloaded very fast using 4k Downloaded.
Now downloading a playlist, 20 videos, videos speed jumps erratically, up and down, from 50 kbps to 2-4 mbps.
But it's still faster than jdownloader, much faster.
Trying 1 single download, works pretty good.

Same video downloads with jDownloader in 2-4 minutes.
Download speed starts at around 500 kbps, then slows down to 30 kbps.
Also tried 1 chunk, 1 download, 1 doenload per hoster = same slow speed.

Found temporary solution: download using both programs, 10 / 7 videos each simultaneously.

And final words: I'm back in full swing: looks like it was a temporary youtube problem, now jdowloader is downloading so fast it desn't have time to compute/display speed (short small videos), something like 15 mbps total for all 10 videos
One single test video (4 hours long) download speed: 15-35 mbps

[Jiaz]

High resolution videos are not throttled by yt but lower qualities are.
Do only use multiple connections/chunks if required. Normally one connection is enough and what you describe is auto throttling by yt. So my guess is that the bypass no longer works.

Would be good to get example links so we can check