numbers app

On smaller spreadsheets it is fast enough. With large spreadsheets it is noticeably slow. It is several orders of magnitude slower than Excel. I tested it once a while back on a very large (but not all that complicated) spreadsheet. I can't recall the exact results but it was along the lines of a split second for Excel to recalculate vs 30 minutes for Numbers.

Use the correct tool for the job.

Unfortunately, there isn't much you can do about the numbers app being slow. Some things to maybe try are using simpler formulas on your spreadsheet if it is having trouble calculating things. Your computer (like mine) was made just before apple started the M range of chips and so applications in newer software versions aren't optimised for intel chips.