zzz has posted the following update:
“I2P network reliability is currently degraded due to a novel and persistent attack. Please be patient as we work on mitigations. If you have not yet updated to the latest release 2.5.0, please do so as it provides some defences.”
For i2pd users, you can try building their latest from GitHub which may help.
More nodes are always helpful I think, but mostly it’s about being up to date. This too shall pass.