if a page has good authority (UR) it will obviously leak more authority into your site via the backlink placed on the page than a page without good UR even if the domain's DR is high.
While DR is great when you're looking to get backlinks from sites with good authority, what you actually want is the page where your link is placed on to have authority (UR) of its own.
The reason for which PBN links are so good is because they're placed on the homepage and the homepage is the page with the most authority (usually), but there are sites (plenty of them actually) out there with pages that have more authority than the domain itself.
Like, for example, it's possible to see a site with DR 13 having a few pages that each one of them has UR of 25, or 37 or whatever other number that's higher than the DR. These pages are usually reserved for selling niche edits (link insertions) off of them (because they have this high authority because they have strong backlinks pointing at them), and which is why niche edits usually cost so much more than guest posts (guest posts always start with 0 UR since they're newly created pages that have no links, although - if the internal linking of the site is good - some of the guest posts do inherit a chunk of the domain's DR as UR within days)...
Anyway, in the context of web 2.0s, as long as they don't have authority (so, UR) themselves and as long as the links you're getting from these web 2.0s are not d0follow, those links will be useless in terms of ranking power (they will still matter as diversity in your backlinking profile, and diversity is needed to avoid clearly recognizable patterns that google might penalize you by)....
So, as I was saying (and sorry for digressing so much), if the web 2.0s don't have authority themselves the links you're getting from them will hardly matter in terms of ranking power. But if they do have authority (so, UR if we're going to use Ahrefs to assess a page's authority), then that UR will trickle down into your site, which could make web 2.0s worth getting if you have the money and patience to build their UR up over months / years for them to become relevant.
That's what I meant, hopefully I explained it well...