Well, of course, I couldn't leave it alone, so I struggled with the extremely slow part and replaced the 39-image album with a 6-image album. Still slow, but at least tolerable enough that I managed to publish locally and then manually transfer the files.
What stands out: the HTML code is actually quite usable. Without a stylesheet, the necessary skips over the navigation and the sidebar are included, and more tags than just DIVs are actually used. However, it also becomes apparent that there are extremely many DIVs with many classes inside - in principle, almost everything is divided. There aren't many P-tags and other logical structures (okay, I haven't written much text, but still, I would at least expect individual paragraphs). It looks better than the HTML from iWeb.
A number of bugs have also been noticed - but it is a beta after all, I don't see that as critically as the exorbitant memory usage. By the way, I deliberately only took one of the predefined stylesheets and didn't change much. I also created a movie page, but somehow the most important thing seems to be missing - the embedding of the movie. In any case, it offered my movie from iMovie but did not adopt it. Well, at least you are spared my silly babbling.