I don’t think you can realistically “pause” the script, you can only hope that the script is written in such a way that it might be able to pick up where it left off.
You might read the comments section at the end of the guide in case the different wording there allows you to understand the limited scope of this method. You have never mentioned a fastbootd screen – notice how the author finds this significant.
I do understand this is very hard when you have no hands on experience of this sort if thing.
There will come a point where you have to say that you have exhausted the fastboot route.
Avoid going beyond what you can understand !
fastbootd is equivalent to booting fastboot into userspace. If you get 2 refusals to boot into userspace it didn’t work.
Edit There is another thing covered in the comments section, that a fastboot method may not be able to downgrade Android version, or Android sub-version. (However remember that you do not want to upgrade Android version ahead of /e/OS version.)