Formula to find&replace part of a string

Question

Column A contains the string you want to edit.
Column C contains a string to find some word in the string in column A.
Column D contains the string that replaces that string.
Results are returned in column F.

This is the result I want.

a	b	c	d	e	f
					result
its test. apple		apple	A		its test. A
its test. banana		banana	B		its test. B
apple & banana		...	...		A & B
banana & banana					B & B
its test. apple					its test. A
its test. banana					its test. B

I used this formula.
=ARRAYFORMULA(VLOOKUP(A2:A, C2:D, 2,TRUE))
and i got this wrong.

a	b	c	d	e	f
					result
its test. apple		apple	A		B
its test. banana		banana	B		B
apple & banana		...	...		A
banana & banana					B
its test. apple					B
its test. banana					B

I want to return only some of the strings have changed. If there are several texts to change in one string, I want to change them all.

Answer 1

You may try:

=REDUCE(A:A,C:C,LAMBDA(a,c,IF(c="",a, INDEX (REGEXREPLACE(a,c,OFFSET(c,0,1))))))

It's a basic REGEXREPLACE, but with REDUCE lets you scan the different words to be replaced

With Substitute:

=REDUCE(A:A,C:C,LAMBDA(a,c,IF(c="",a, INDEX (SUBSTITUTE(a,c,OFFSET(c,0,1))))))