Slows down then freezes sure sounds like an out of memory situation, so to add to yours here they might actually want less swap. Sometimes you would rather hit the oom killer sooner instead of waiting on swap to fill.

Ideally login via SSH from another machine to figure out what is using the memory (hopefully the system is responsive enough for SSH), and if it is your critical programs causing the problem then you should consider a memory upgrade.

In any KDE app you can connect with SFTP in the open file dialog. Just type sftp://user@server/path and you can browse/open/edit files the remote server. ssh keys+agent make things a lot easier here obviously.