Do screening criteria only apply to listed companies or also to non-listed companies?

Selamaleykum dear Zoya team and community,
Thank you very much for your work. You enrich many people with it and make it easier to find your way in the investment world. The community offers a great opportunity to discuss and exchange ideas!

Concerning the screening criteria, I would like to know if they only apply to listed companies or if non-listed companies (e.g. small and medium-sized companies) can also be evaluated in this way? Especially the financial criteria would be important here, since the business criteria can be surely transferred in such a way?

Can anyone recommend books or papers on the subject of business valuation in Islamic finance? Whether e.g. DCF methods with discounting is allowed etc.?

I look forward to the exchange!

Greetings and selam
Usama Abbas