Perhaps some kind of service where a {node A} can advertise a sidekick/spillover channel address, that sats can pour in to, if there's no capacity into {node A}. The sidekick/spillover addresses could be run by custodian whom you would have to trust with small amounts, for small durations (until you sweep the sats out). These services could charge maybe 2%-3% (auction market) to sweep sats back out.
Discussion
I already have that, actually. My ln.do service sort of doing that but not exactly. It tries to fetch the invoice from my node, and if it fails, it tries a backup (WoS or Alby) and presents that to the user. I know it’s not the same, but works for me for now 🐶🐾🫡