I found out a regex pattern to remove all non alphabet letters: \p{L}
I thus did a regex to remove all non alphabet, non digit and non underscore pattern : /[^\p{L}\d_]/gimu
Unfortunately, it does not work with a hindi character like #फ्रांस
which gives फरस
See for yourself here https://regex101.com/r/dnXDK0/1
And please help me :-)