Combine column cell interchangeably in one column

Question

Let us assume we have the following tow columns :

column 1

1
3
5

column 2

2
4
6

the result column

1
2
3
4
5
6

and in case the two columns are not equal in size, the combined result should be without empty cells at the end!

Answer 1

=FLATTEN(A1:B)

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=TRANSPOSE(SPLIT(TEXTJOIN("♦", 1, A1:B), "♦"))

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=INDEX(TRANSPOSE(SPLIT(QUERY(TRANSPOSE(QUERY(TRANSPOSE(
 IF(A1:B="",,"♦"&A1:B)),,99^99)),,99^99), "♦")))