Square root of a negative number squared √x^2=|x|,
What about √-x^2 ?
If we use the number $5$ as en example,
would this evaluate to √-5^2 = √25 =5
OR do we need to get the imaginary number 'i' involved, resulting in √-5^2 = 5i
I have found many conflicting answers
Any clarification on the topic would be much appreciated

Kind Regards
In real numbers, the square root of a negative is not defined.

$$\color{red}{\sqrt{-25}}.$$

In complex numbers, the square root of a negative can indeed be defined as $i$ times the square root of the absolute value.

$$\sqrt{-25}=5i.$$

But you need to understand the concept of principal branch, as $-5i$ could also be an acceptable answer.
The answer is ±5.

$-5$ is converted to $5i^2$ then squared, resulting to $25i^4$, according to the PEMDAS rule.

The root of $25i^4$ is then evaluated by taking the roots of a complex number. Note that $z = r(\cos\phi + i\sin\phi)$, where $z$ is the $n$-th root.

$r$ is the real root part, but in this case is used to contain imaginary numbers as well. Therefore, $r = \sqrt{25i^4} = 5i^2$, without regard to sign.

$\phi = 360°/n$, where $n$ is the $n$-th root. Thus, $n = 2$, therefore $\phi = 180°$.

Using the argand diagram, there are two cases, $\phi = 0°$ and $\phi = 180°$. Evaluating $z$, we have $z = -5i^2$ ($\phi = 180°$) and $z = 5i^2$ ($\phi = 0°$), giving us $z = ±5$ upon simplification.

The only thing I am not so sure about is if it is allowed to use imaginary numbers in $r$, as this is counter-intuitive from its derivation, and I'm gonna confirm it with my math doctor.

Hope this helps.