Thank you! Perhaps I should add the supported functions in README.md. There is a list in programme's help (F1) with a small summary from each one. I copy from there:

ABS, AND, AVERAGE, AVERAGEIF, COLUMN, COUNT, COUNTA, COUNTIF, COUNTIFS, DATE, DAY, DAYS, EXACT, EXP, FILTER, FIND, HLOOKUP, IF, IFERROR, IFNA, IFS, INDEX, INDIRECT, INT, IPMT, ISBLANK, ISERROR, ISNUMBER, ISTEXT, LEFT, LEN, LET, LN, LOWER, MATCH, MAX, MID, MOD, MONTH, NA, NOT, NOW, OFFSET, OR, PI, PMT, POWER, PPMT, PRODUCT, RIGHT, ROUND, ROUNDUP, ROW, ROWS, SQRT, SUBSTITUTE, SUBTOTAL, SUM, SUMIF, SUMIFS, SUMPRODUCT, TEXT, TEXTJOIN, TODAY, TRIM, TRUE/FALSE, UPPER, VALUE, VLOOKUP, WEEKDAY, XLOOKUP, YEAR,

Regarding the 2nd part of your question, I quote from the LLM: Complex scalar formulas with deep, cross-sheet, and indirect dependencies are fully evaluated with cycle safety; range/array inputs compose inside aggregations, but dynamic-array spilling is not implemented — multi-cell results surface as #VALUE! instead of spilling.