Isn’t the paper that you are using as evidence that ribozymes have low error rates out of date? Cells that use ribozymes and RNA only are not in evidence in nature, and at the time that the paper that you mentioned was written the author stated:
Nobody has yet seen or constructed a functional riboorganism, but we know how mutations affect the functionality of certain ribozymes.
This statement includes both a fact and an opinion, it is a fact riboorganisms do not exist in nature, but were imagined by OOL theorist as a hypothetical organism that if it were able to exist could be seen as an evolutionary ancestor of modern cells. Speculation is great but it never should trump actual empirical evidence, which is what the 2020 paper that I mentioned was referencing. He referred to a real life ribozyme that was after 14 rounds of guide evolution and the help of advanced chemical engineering able to make a copy of it’s own ancestor, something that a ribozyme would have to do autonomously in a hypothetical RNA only, cell if RNA world actually existed. The paper that the author of the paper mentioned can be found in the link below:
https://www.pnas.org/content/117/6/2906
And it was this empirical evidence derived result that led the author to write:
Does this help us to understand how an RNA world could have arisen? On the contrary, it points to another problem. The best RNA polymerase the researchers obtained this way had a roughly 8% chance of inserting any nucleotide wrongly, and any such error increased the chance that the full chain encoded by the molecule would not be replicated. What’s more, making the original class I ligase was even more error-prone and inefficient – there was a 17% chance of an error on each nucleotide addition, plus a small chance of a spurious extra nucleotide being added at each position.
So if they is experimental evidence that a RNA molecule that can be guided to self replication has a lower error rate great. But it surely isn’t in a paper written 15 years before the experiments that the author was discussing.