The script does appear to be some Asiatic language from India (probably northern), Pakistan, Nepal or that kind of region. The reason the characters in the 3 x 3 grid seem not to match the script is that they’re numerals not letters. I would guess Sanskrit, Hindi, Nepali or some related language.
I believe it’s a “magic square” where the sum of the numbers in each column and row is the same. Commonly seen on ‘ritual’ items from that part of the word. These examples are in Sanskrit:
View attachment 2078114
I would think the fact it came out of the sea is significant and that it’s some kind of ritual item relating to a religious festival, funeral rite, or other ceremony where such items are deliberately cast into the water. People continue their homeland traditions wherever they happen to have relocated.