There used to be an exclusion group (at least for contacts) on iPhone, but I haven't used one in a while - not sure if that is still working the same way it did. The downside of a separate phone is that you have to charge it.
I auto-compact with the default min-age, but LND writes to an oversized and more performant/resilient separate volume. This was problem was bitcoind running out of storage.
Node back up. Our bitcoin node ran out of disk space. Sorry yall.