I have actually read the paper. I agree that the paper is more cautious in its claims than the press release from the University and from the news articles that followed. The news articles did make it sound like the experiment had discovered a self-replicating RNA. Here are two examples:
"According to SciTechDaily.com, the first RNA molecule that can replicate itself was created, thanks to scientists from the University of Tokyo."
Source: https://www.healththoroughfare.com/science/scientists-create-the-first-rna-molecule-that-replicates/45320
AND
"AN RNA molecule that can self-replicate, change its form and develop complexity - or, in other words, evolve - has been developed by researchers for the first time in a discovery that could shine a light on how life first emerged."
from: https://www.express.co.uk/news/science/1582670/origins-of-life-breakthrough-evolving-rna-molecule-created-first-time-tokyo