Unman makes a good point. If you state your need, someone might point you at something more specific.
The more complete process is, for you specifically to do a Risk Assessment. What is your specific Risk.
Both Unman- (who does a lot of helpful Qubes things), and Sven (who keeps up with the HCL -the list of which pieces of laptop-hardware run Qubes, (How easy it is to implement) Both are more knowledgeable than myself.
If your perspective is the same as mine – I am poor. For me, it is what will reliably work that I can afford. I have purchased a refurbished Lenovo Think Pad X-230, and a Lenovo Thinkpad T430.
Each cost me about two hundred US dollars.
They both lack several needed hardware upgrades. RAM upgrade to 16 GB is likely a hundred. After I can get the basic computer to accept it, I will put in a better WiFi Adapter. I know that the BIOS/EFI, which comes with the ThinkPad will only power up with the original Intel WiFi Adapter, and later WiFi Adapter perform better (in distance to source, and faster)
These two laptops, after further modifications form the basis for Qubes “Certified Laptops.” The process of a laptop becoming a certified laptops is described at the bottom of the Qubes OS page.
I think I have written too many details. That is the nature of accomplishing Secure - computers. Details. . The saving Angel is in the Details.
Now, If someone can give a website to suggest the process of how to do a risk assessment. I could search, but I do not know what are the best websites for that.