An echo chamber happens specifically when a group's internal belief's enter a positive feedback loop and become insulated from any external (and often internal) dissent.
What you've described sounds more like a group with common belief's that has not devolved into an echo chamber. And that is what we should all strive for.
another relevant phenomenon derived therein is that a range of opinions, most of which are wrong, is completely normal and acceptable, as far as reasonable group decision-making goes.
but correlation of opinion is the core issue here, and human social dynamics constantly corral us into such correlations. only folks sufficiently and intrinsically principled have a strong enough will to incur the social costs of having truly independently-derived opinions from the herd (which doesn't guarantee objectively better perspectives either, but does help the herd hedge against catastrophic over-correlation).
"Do your own research" is the "trust no one" of the 2020's. Anyone who says it simply wants you to go away and isn't interested in debate and is unwilling to accept any information that might imply that they are wrong. If someone says "do your own research" to you and you are not both currently scientists working in the same field then it is safe to ignore them and everything they have ever said (and quite possibly everything they ever will say).
As for trust or distrust in authorities. There are many authorities that give you a good reason to trust them, namely a track record of telling the truth and acting in your best interest. There are also many authorities that give you a good reason to distrust them, by abusing their authority for personal profit, exposing themselves as an enemy, or selling out their built up goodwill to the highest bidder.
If there's no willingness to accept that a belief is mistaken then there's no room for reason.
I've gone through a lot of different echo chambers in my life. From a traditionalist Catholic school to an ultra-liberal public university, and then spent time trying to orient myself and bouncing through a few different ideologies.
Some lines of thinking I've used to determine if I've found the right echo chamber, which, thankfully, I now have.
1. Is the world-view grounded in positive rhetoric? Do the practices and beliefs encourage building up both group members and the group as a whole? If not, there's a good chance you're being manipulated to serve someone else's purposes.
2. Does the group encourage you to think and reason for yourself? You're choosing this group so that you don't have to think about everything for yourself. But in the end you are responsible for your own life, so if a group is telling you to defer to an outside authority, tells you not to critically think about decisions, or tells you that certain topics on inquiry are off limits, stay away.
3. Does the world view accurately predict what will happen? Many ideologies are great at shoe-horning their narrative on past events, and many are great at coming up with logical arguments that are meant to be confusing and hard to refute, but the proof is in the predictive nature of the world-view.
4. Related to the above, when there's a failure in world-view, does the group have a mechanism of incorporating and learning from those failures?