NetworkTweaks is a Valheim networking mod that raises the Steam data transfer rate limit and lets you configure how many peers receive sync data each update tick. It must be installed on both server and client and will block mismatched versions.
With its built‑in file watcher, NetworkTweaks lets you adjust settings on the fly via the config file or an in‑game config manager. Not compatible with ReturnToSender, Network, and likely other networking mods.