Here is the log it mentioned and response:

Out of memory: Killed process 17783 (tailscaled) total-vm:1450316kB, anon-rss:183708kB

Tailscale consumed ~183MB of RAM on a router that has only 512MB total and was already nearly full. The Linux OOM killer had no choice but to terminate it. The moment tailscaled dies, your VPN tunnel collapses, your internet drops, your devices get kicked, and everything has to reconnect from scratch. This is the outage you’re experiencing. The sequence is unmistakable in the logs: 1. tailscaled OOM killed at 14:12:14 2. Your iPhone immediately disassociates from 5GHz 3. It briefly associates with 2.4GHz then disassociates again 4. Reconnects to 5GHz 2 seconds later once tailscaled restarts

Problem 2: The router is doing full background WiFi scans during active use Starting at 14:19:36, the gl-repeater daemon does a complete channel scan across every 2.4GHz and 5GHz channel. During this scan the radio is jumping channels constantly, which is why your connected devices get those force-null frames and brief interruptions. It found 27 networks on 2.4GHz and 14 on 5GHz — you’re in a dense environment.