正则表达式查找最小长度的句子

我正在尝试创建一个查找具有最小长度的句子的正则表达式。

我的条件确实是:

  1. 序列中至少必须有4个字
  2. 顺序中的单词必须不同
  3. 顺序后必须加上一些标点符号。

到目前为止,我已经尝试过

^(\b\w*\b\s?){2,}\s?[.?!]$

如果我的示例文本是:

This is a sentence I would like to parse.

This is too short. 

Single word

Not not not distinct distinct words words.

Another sentence that I would be interested in. 

我想匹配字符串1和5。

I am using the python re library. I am using regex101 to test and it appears the regex I have above is doing quite a bit of work regards to backtracking so I imagine those knowledgable in regex may be a bit appalled (my apologies).