Applying Justify alignment across block content

Hi there

I have made a couple of WordPress sites using normal, old school text editors and the page creation sytem, which I am comfortable with, but not using the new Gutenberg Block system, which right from the beginning found too cumbersome to learn and use.
For the described problem, using the old system quickly solves the problem, but one is obligated to use the Block system in this case.
A friend urgently needs to create a site for a school project using this Kadence theme, but has problems having to format each paragraph with this “Justify” text alignment, which is quite cumbersome.
He further said, whenever he tries formating each paragraph that way, it causes some problem, probably the with navigation or some other menu or other layout issue, I do remember as of now.
The site unfortunatey cannot be viewed publicly yet to see what problem he is having.

My request is for advice on how to apply this page content “justify” across similar block content on a page for the whole site without having to format each paragraph/block separately. As much as I know, he needs this for page content, which if I am not mistaken is created in blocks(?).
Using the Classic Editor + Advanced editor tools plugins, this would easily be solved by selecting all that page’s content and clicking the “Justify” button, which he cannot use in this Gutenberg Block sytem case (or can he & if so exactly how?).

Not being a coder, could someone please use a simple explanation on how to achieve this?
Also not being conversant with this Gutenberg block system, can one apply under the theme’s Customizer => Additional CSS some custom style to deal with this as said, impose “justify” to page content in blocks and if so, exactly what style would have to be added?
I would very much appreciate your kind and specific solution to this.

Thank you in advance