Glad you walked away from this, sounds like there were a number of opportunities for a far worse outcome.
On a general point: over the years I’ve owned my Commander I’ve never managed to carry out my biennial flight with any instructor having more than a few hours on type. I love watching them jump out of their skins when the gear alarm bell starts off, wonder why they yaw all over the place during retraction and react way too late when the nose points towards the left edge of the runway when they open the throttle. My “Watch This”! Moment came when one instructor insisted I was rotating at too high a speed, his PA28 experience shone through. I asked him to demonstrate this new take off technique and he diligently tried to lift the nose at 55, you can guess the rest.
The reality in this country is that most Commander owners are flying their biennial with instructors with no Commander experience, often as part of an IR or other rating renewal, often not even in a Commander. There is no requirement here to do a biennial flight in a high performance aircraft, EASA doesn’t even have that category, SEP is anything with a piston engine and one prop. There is no set plan for a biennial flight either. You can do anything with an instructor onboard and as long as it’s an hour flight.
Perhaps the downturn in airline jobs will mean the hour builder instructors will be replaced by seasoned out of work captains with a little more real world experience.