@astridx
Maybe I did not express myself correctly. I do consider the chevron a back and forth indication.

After your patch for LTR
When we get to the first display of Install Additional Languages
I think we should keep the chevron after the text to indicate going to next page.
I.e. we should not do

but keep

But here, instead of this

We should have this to indicate that we go backward

Obvioulsy the opposite in RTL

The main problem is to differentiate the 2 views..

I got it wrong. Where do you see exactly going back?

@infograf768 Obvioulsy the opposite in RTL

I just took a closer look at it. Is RTL used in the installation at all?
If I set Persian as the default, it's still LTR, right?

I got it wrong. Where do you see exactly going back?

Once you have installed one language with Next, you get to the list of installed languages to select default.
Clicking again on Install Additional Languages is what I call "going back" as we get back to the list of all languages we can install.

I tested RTL by adding the 3.x fa-IR installation lang folder to J4 and choosing it as installation language. This is independent of the installation of the Persian language later on in the process.
It looks like we have issues with many icons (including the chevron but this case is explained above) which should display at the right of the text instead of left.

Clicking again on Install Additional Languages is what I call "going back" as we get back to the list of all languages we can install.

Hm. I think that's a matter of opinion. For me it is a new step forward.

I tested RTL by adding the 3.x fa-IR installation lang folder to J4 and choosing it as installation language. This is independent of the installation of the Persian language later on in the process.

If I looked right, then RTL is not used for the installation.

RTL is used if the language for installation is set as rtl. Just add the J3 fa-IR installation lang folder and select it when installing.

and then

Only small hitch below: the "Complete & ..." icons are placed to the left, they should be to the right (not a release blocker)

This hitch can be solved by taking off this in the rtl template.scss

.j-install-last-step .fas {
  display: inline;
}

then we will get

RTL is used if the language for installation is set as rtl. Just add the J3 fa-IR installation lang folder and select it when install

Thank you, I had only seen the two languages available and did not know that others would be added.
Is that how you imagine it to be?

(I didn't spin the arrow. I think that you always go forward to languages. After installing, you go back to the finished site. If you want to install more than one additional language you go forward again ...)

@astridx
why not just delete the inline ?
.j-install-last-step .fas {
display: inline;
}

@astridx
why not just delete the inline ?
.j-install-last-step .fas {
display: inline;
}

Because I do not understand why this display: inline; was set and therefore do not want to delete it. I'm not sure if that will affect anything else. You also don't have to do npm ci like this for testing.