“but minimum screen brightness, absence of pulse-with modulation,
presence of touchpad buttons, ability to disable touchpad tapping and
gestures, ability to use the keyboard with one hand without strain, etc.
also matter. and aren’t in most reviews,”
I see. I know what it’s like to have peculiar requirements that are hard to find out about via standard reviews. So, my sympathies for your difficulties.
If you aren’t able to go look at and evaluate to your satisfaction candidate laptops in person at a local brick and mortar store, then your next best bet is to ask for help on a forum like the thinkpad forum I mentioned. Start by narrowing the field down to a reasonable number of candidate models that might work for you in terms of the specs you can check online, and then ask questions and hopefully you’ll get helpful replies. Try to stick with business class laptops and popular form factors so it will be easy, once you figure out which ones will meet your needs, to find an affordable refurbished model for sale online.
Good luck.