Reachability problems on actively hostile networks rarely have a single answer. The healthy posture is to assume the network changes, your needs change, and the tools you have available change with both. Here is a practical playbook that tends to work.
Have more than one node. The directory shows multiple options; pick three or four candidates spread across countries and ASNs. When one stops working, switch. The exit you used yesterday may not be the one that works today; this is normal, not a sign anything is broken on your end.
Pay attention to time-of-day patterns. On some networks, weekday business hours are when DPI inspection is most aggressive. Late evenings and weekends are looser. If you have flexibility on when to do the bandwidth-heavy work, this can matter.
Keep a fallback for the specific tasks that matter. For "I just need to read this article", a single drop is annoying. For "I'm in the middle of a video call", a single drop is the meeting. Have a Plan B — different node, different network (mobile vs Wi-Fi), different timing.
Don't accumulate "what worked once" lore. Configurations that worked in March stop working in April. The temptation to write down "use node X with setting Y" is real and the resulting cheat-sheet is a trap; it tricks you into thinking the problem is settled. Treat the answer to "what works" as something you re-test periodically.
Use the starter balance for testing. The point of the starter balance is exactly this: to let you check whether the service works on your specific network without committing to a voucher. If a node fails repeatedly during the starter period, do not buy a voucher and assume it'll work later. Buy when the test confirms the configuration works.
Avoid public discussion of what's working where. Forum posts and screenshots showing "QPOL works on carrier X in country Y" age into adversary intelligence. We deliberately don't publish a status board with country-by-country reachability for the same reason. The information has a half-life measured in hours when adversaries pay attention to it.