Nesting XLOOKP Operations or use something else?

Using Excel 365.

I have large tables for some chemical data that I need to do various look ups to return other corresponding data points. I've used XLOOKUP with great success so far but I've tried a nested XLOOKUP up for a slightly more complex situation. Please see below for images illustrating the assessed flow of how I think this operation should work to reach the desired end state (the last part of the image got cut for some reason, see the PDF for full final image). Ive attached the images in a PDF and the excel file for experimentation. Any insight or suggestions would be greatly appreciated. I'm not married to XLOOKUP either, it just seemed like a logical choice.

01-06.png

In B18, try this:

=LET(a,XLOOKUP(A9,E2:S2,E4:S22,,0),FILTER(a,SEQUENCE(COUNT(a))>=MATCH(A13,a,0)))

In A18, try this:
=FILTER(F4:F22,SEQUENCE(COUNT(F4:F22))>=MATCH(A13,XLOOKUP(A9,E2:S2,E4:S22,,0),0))

Thank you Greg, your solution worked perfectly! And as an added bonus I've learned how to use those additional functions.