A9+ Keyboard

[TJD_Mee]

Takes about 6-10 taps on every letter to respond to input.

[_nok_]

Is it happening even after the phone restart?

Also, try clearing up the cache. Search Samsung Keyboard in Settings > App and clear it there.

[TJD_Mee]

Still occurs

[SamsungDeviceLiker]

Is it on the physical or software keyboard?

[TJD_Mee]

Software keyboard

[SamsungDeviceLiker]

Try using GBoard or another keyboard app to see if the problem is with the device or the Samsung Keyboard Software.

[Troubadour]

If A9+ has it, go to Settings and search for Touch Sensitivity

[TJD_Mee]

Already increased

[Troubadour]

I think I have to give up, no further suggestions. If you improve things or solve it please advise. Note that in the keyboard you can change the default keyboard, e.g. swap from UK to US keyboard and vice versa but I presume you have tried that already.

I suppose if you have a screen protector on you could remove it and try a thinner one but I am wary of suggesting it having broken a screen myself earlier this year.