Many “boutique” retailers will only offer 3 (if you’re lucky) turntables to compare.
One of these might be a potential candidate.
It’s unlikely you’ll be able to compare with the alternates from your shortlist.
They might be able to demo same arm & cart but it might involve swapping.
If it doesn’t involve swapping the samples might sound different anyway.
Even with “identical sounding” samples (an impossibility in my view) the setup will vary slightly for each one.
Even if you notice what’s wrong how long is the demo going to take before all setups are optimal?
(“Setup” also means mechanical support, cable dressing etc)