>I know what features it claims to have.

Yeah...no i don't think so.

>IMHO you can't really have interactive chat on a mesh network over lora in those bands.

Devices allow 10% Airtime on ISM here (EU) that's about 300 messages (with 255 characters) per hour, and yes interactive chat is possible with around 20 seconds of lag.

EDIT: I stop here, so much half knowledge that sounds educated but is in fact just wrong and TBH not even sure if i talk to a selfhosted AI.

Have a good Day.

Yes, in the EU one subband allows 10%, the rest is 1%. I believe that Meshtastic uses the whole 250kHz of that subband by default. This is by far the most relaxed constraints of what is available in the EU and US. That's about 180 max. size messages per hour (at longfast) per device but you need to take into account retransmissions, acks, mesh management and routing of third party messages. So it may work, barely, for this specific config and very small number of people or 1-to-1, but that's it.

I am not picking on Meshtastic specifically, it's just that Lora and, especially the regs on those bands are such that some applications are never going to work well beyond extremely small meshes, if at all.

>I believe that Meshtastic uses the whole 250kHz of that subband by default. This is by far the most relaxed constraints of what is available in the EU and US.

Again wrong, just look at EU vs US:

https://meshtastic.org/docs/configuration/radio/lora/#region

> beyond extremely small meshes, if at all.

180 online nodes (300 at max) is not extremely small (and that's our small mesh EU with medium_fast)

How many text messages does each user send per hour? Or how many are in active chat with each others at a given time?

(Careful that the US have a 400ms dwell time depending on settings that can put a significant limit on things/range)