I don't think one hundred is enough of a sample size to suggest it's too easy. In real life players have done well early on and never bettered that. I just scored 240 but after a run of five non-fifties so can I back it up? Unless we're averaging 60+ and getting 100s every two or three innings then it may not be too easy. Remember that the AI opposition are club players, when you get to first class level etc then yes your rating will be higher but the players around you will rate from around 55-90 odd not just 38-49 or so.
You say 161 not out from 122 balls which suggests you are still playing 'properly' with some big hitting as well. If you're hitting every ball for six and never mishitting it and getting out cheaply and therefore not reverting to constructing an innings, just smashing it then that's when it's too easy. Obviously you want to be challenged so move to the next level (I can never remember which way around veteran and legend are!) if you want. The higher the level both the more rewarding and frustrating it can be.
I've switched to the standard buttons having played previous games. It's simplified but varied enough. Let me know if you beat my 240.
Which country's league are you in?
Do all opposition seem to have right arm and left arm pace and spin? I haven't faced any dibbly dobbly bowling that was prevalent in DBC 17. It's out and out pace or spin.