"Decipherment" is meaningless without an extant corpus to compare it to.

Traditionally scholars have looked to the 23 or so tablets for the corpus. Die-hards have added oral traditions from Rapa Nui that have been recorded in English/Spanish and a mix of Old Rapa Nui and Tahitian. There are two sources thoroughly considered in this research that helped to extend the corpus considerably. Tregear's early Maori-Polynesian comparative dictionary. He attempted to exclude late additions to the language due to European influences. He also included a number of myths and rituals associated with the words he found. Which leads to a second source, broader Polynesian mythology and chants recorded in their original languages (close to being dialects of Old Rapa Nui). That is, there are between 1000 and 1500 years from the separation of the people of Rapa Nui from the clans of Hawaii, New Zealand, Tahiti and so forth. Consider the separate of Latin from the surrounding Romance languages. Many words can be identified. Tregear's dictionary identifies which words are most common across Polynesia. They tend to be those words associated with the most sacred rites and mythical stories. These words were found to parallel with symbols on the tablets. Since the Rapa Nui Tablets contain both syllables and logograms (like ancient Egyptian), flag logograms lead to an identification of syllables. Like pieces off the Rosetta stone, early Polynesian chants began to show up in the decipherment....

to see that the link is pretty weak sauce scholarship.

Initially the research focuses on Indigenous world-view and later on develops the scholarship attempts that have been made thus far