We don’t need to replace the ‘ch’. We can replace the ‘c’ with a ‘k’ when it makes a ‘k’ sound, like in cougar or caramel, and with an ‘s’ when it makes an ‘s’ sound, like in century or cilia. Then we can use the ‘c’ character for when we use ‘ch’ now.
If we are gonna do it then we need 29 so we can have a character to replace ‘ch’ and ‘sh’ as well.
We don’t need to replace the ‘ch’. We can replace the ‘c’ with a ‘k’ when it makes a ‘k’ sound, like in cougar or caramel, and with an ‘s’ when it makes an ‘s’ sound, like in century or cilia. Then we can use the ‘c’ character for when we use ‘ch’ now.