In this case you should say “find every sentence doesn’t end with a dot”. So try this:
in Find: \u[^.]+?(?=\u)
in Change: $0.

Yes! Exactly “Extended Undo/Redo – Marijan Tompa (tomaxxi)” This is exactly what I was referring to, but I did not find a download link to share at the time.
Thank You Mike!

Use this:
in Find: ×\d+\K\.|\.(?=\d+×)
in Change: ,

Use this:
in Find: \<n\K(os?)\.?
in Change: $1
in Change Format: Open type superscript

Should be someone on the other side of the earth to guard the forum in the night

If you change some setting in the new paragraph, won’t update again when you change it in the master paragraph

You can do it automatically by using GREP Style
First create character style for the new apostrophe, then copy the old apostrophe and paste it in “To Text” field