if(TODAY()=DATEINMONTH(TODAY(),-1),DATEINMONTH(MONTHDELTA(TODAY(),-1),-1),DATEDELTA(DATEINWEEK(today(),5),-7))

修改后

if(INARRAY(WEEK(TODAY()), UNIQUEARRAY(MAPARRAY(RANGE(DATEINMONTH(TODAY(), 1), DATEINMONTH(TODAY(), -1)), WEEK(ITEM))))=1,DATEINMONTH(MONTHDELTA(TODAY(),-1),-1),if(or(weekday(today())=0,weekday(today())=6),"",DATEDELTA(DATEINWEEK(today(),5),-7)))

公式解释

INARRAY(WEEK(TODAY()), UNIQUEARRAY(MAPARRAY(RANGE(DATEINMONTH(TODAY(), 1), DATEINMONTH(TODAY(), -1)), WEEK(ITEM)))) 第几周 第一周就返回上个月最后一天，

or(weekday(today())=0,weekday(today())=6) 周六日 不是周六日 就返回上周五

测试了一下，有的地方不需要转，有的又需要 有点怪

if(INARRAY(WEEK("20220703"), UNIQUEARRAY(MAPARRAY(RANGE(DATEINMONTH("20220703", 1), DATEINMONTH("20220703", -1)), WEEK(ITEM))))=1,DATEINMONTH(MONTHDELTA("2022-07-03",-1),-1),if(or(weekday("20220703")=0,weekday("20220703")=6),"",DATEDELTA(DATEINWEEK("2022-07-03",5),-7)))

修改

if(ROUNDUP((DAY("2022-06-12") + (IF(WEEKDAY(DATEINMONTH("2022-06-12", 1)) = 0, 7, WEEKDAY(DATEINMONTH("2022-06-12", 1)))) - 1) / 7, 0)=1,DATEINMONTH(MONTHDELTA("2022-06-12",-1),-1),if(or(weekday("2022-06-12")=0,weekday("2022-06-12")=6),"",DATEDELTA(DATEINWEEK("2022-06-12",5),-7)))

没有太明白你的需求。。。举例说明结果吧。为什么是这样的结果，红黄的内容完全没有看懂 为什么2022-12-02是显示2022-11-30？。12-01的时候又显示什么？11-30的时候又显示什么？没有太明白你的计算逻辑