Google-sheets – Number in a cell linked with a text

One can't have both data and a formula in the same cell. If you want B4 to change in response to changes elsewhere (and don't want to write a script), then B4 must contain a formula. Then the data (such as "4, 7, 8, 5H") must be elsewhere. In my example, the data is in A4 but it could be any cell. Here is the formula for B4:

=join(", ", split(regexreplace(A4, iferror("(?i)\b("&join("|", filter(E4:H4, len(E4:H4)))&")\b", ""), ""), ", "))

Explanation:

1. iferror(join("|", filter(E4:H4, len(E4:H4))), "") joins nonempty cells in the range E4:H4 into a regular expression such as 7|abc|5H
2. The regex is wrapped in word boundaries: \b(7|abc|5H)\b, so that 7 does not get removed from 7H, for example.
3. It is made case-insensitive with the flag (?i), so that 2h is treated the same as 2H.
4. regexreplace replaces the above with empty strings
5. The split-join operation takes care of empty places left after replacement. For example, if regexreplace produced 4, 7, , 5H then split-join will make it 4, 7, 5H.

A script might be a better way. As far as the formula goes, You can combine both arrays using {}

=ARRAYFORMULA({QUERY();QUERY()})

Problem is that Columns in First query should be equal to Second query or vice versa. Another problem is time taken to import both ranges. If it differs significantly, arrayformula might fail. If the second QUERY is 13 columns, You might need to fill up the other columns with numbers or spaces.

=QUERY(IMPORTRANGE(),"Select Col1,Col2,3,4,5,6,7,8,9,10,11,12,13 where Col1 = 'What' format 3 ';;;' ")

The above formula creates original 2 columns and the rest of 11 columns are filled with corresponding numbers. You can use the format to hide them ( the above code hides number 3 column).