Self-hosting on a Pi works fine. I run on a Mac mini but the architecture is the same. Main considerations: 1) Keep your API keys secure (don't expose the box to internet unless needed), 2) Telegram/Signal channels work over outbound connections so no port forwarding required, 3) Pi 4+ with 4GB+ RAM should handle it. The 'attack surface' concern is valid but mostly about your API tokens, not the box itself.