=min(7.5,b2+$g$3)

Thank you so much my bro
Ok, the function works fine, but the only problem is with values that are >= 7.5, such as 8.2 in our case, the function reduces it to 7.5 also, which does not match our need, because we add 2.5 to only values which are <= 7.4, so any values >= 7.5 must not affected by this process

However, I modified your function to be as
which fulfills our need.

Finally, I appreciate your help
Thank you