Oh, and the downloaded PDF manual at one point stated that I must only cut insulation with it, not wood! Cut and paste problem from the SSU 300 manual perhaps.

To be fair, your retailer may not necessarily be familiar with saw-chain equipped power tools.  It's surely a more specialised field than circular saws, etc.  Now if s/he'd supplied your new plunge saw with an inverted sawblade..... well I'd consider changing suppliers.

Chainsaws are funny things.  The bar is symmetrical, meaning there's actually no "right way up".  A bar can be easily & effectively installed "upside down" or "backwards" & still be correctly, perfectly functional;  providing the actual chain is installed facing the correct way in relation to that installation.  Yes, it's a silly, stupid mistake, but not all that impossible to achieve.  Even after over 50 years of use it's not unusual for me to absent-mindedly do the same.  In that 50 years I have also - twice to my eternal embarrassment - fuelled a saw with pure petroleum, all but instantaneously overrevving & destroying 2 sets of expensive piston rings!

As for attempting to cut with an inverted chain.... the horrendous noise of ill-fitting drive links attempting unsuccessfully to mesh with a drive sprocket should've alerted you immediately that there was summat seriously amiss well before the first cut.

I’d like to see a picture of a cut, both with and across the grain. Don’t worry about picture orientation.

Thanks for the pic. That cut isn’t bad at all considering the blade.

That wood though, it really grew fast didn’t it.