I should probably just reinstall my system and replace it with a distro that has newer versions of stuff.

You could do that. Although if it's just java you need, debian ships multiple versions. Openjdk 17, 21 and 25 are all available in Debian 13.

Sounds good. Hopefully it should take the edge off.

Qbittorrent's official flatpak, despite being the latest release, is built with libtorrent-rasterbar 1.something. Qbt i2p support is dependent on libtorrent-rasterbar 2.0 or greater. Just putting this here because I experienced the pitfall of wondering why the hell my latest version qbittorrent didn...

Bit of a shot in the dark solution here, but have you tried increasing the memory that i2p's java wrapper has access to? I've found doing that made everything run smoother for me.

It's done by editing /etc/i2p/wrapper.config