Reproduced the same issue on LMDE 6 (based on Debian 12)
This issue may be related to https://github.com/ValveSoftware/steam-for-linux/issues/10248. Do speeds improve if you apply the tweaks suggested there?
Welp, that's awkward, now I feel stupid that I haven't found that sooner. It does seem to improve the downloading speed significantly. Still not as fast as on Windows, but much faster nonetheless. Thanks!
You should keep this open because, just setting those in steam_dev is not a solution. I'm on a 8gig symmetrical fiber connection on Arch Linux have those settings its a little faster but I should be able to max out my line like I can with Heroic Game Launcher downloading from Epic game store lol. Steam (Valve) needs to fix the root problem.
Yeah, there's one thing I forgot to mention, whenever there's an update for the Steam Client, it also downloads painfully slow, and this HTTP2 toggle doesn't affect it either.
Your system information
Please describe your issue in as much detail as possible:
When I download a game from Steam on Linux, the download speed is painfully slow. It's not consistently slow, it can be 2 MB/s, or 10, or 20 if I'm lucky. Changing the server barely helps. Trying to download the same game on Windows (on the same machine, virtualized) results in Steam consistently hitting my ISP's bandwidth limit, around 80 MB/s. The ISP is Ufanet, if that helps. All the network settings are as they come by default, untouched. The issue has been bothering me ever since I switched to Linux, persists through multiple reinstalls, different distros and also happens on my Deck running vanilla SteamOS.

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