I mean objectively speaking you're wrong on both accounts BUT I'm not sure what your personal definition of "defense being better" is either. It's the best defense Banks has fielded, statistically in his tenure here.
2023: 20.2 ppg, 340.6 total yards allowed, 66% passing, 227.5 yards per game, 113.1 rushing, 1.4 turnovers a game
2022: 22.8 ppg, 405.3 total yards allowed, 62.6% passing, 289.5 yards per game, 115.8 rushing, 1.6 turnovers a game
2021: 23.1 ppg, 421.7 total yards allowed, 61.2% passing, 273.2 yards per game, 148.5 rushing, 1.2 turnovers a game
As for Joe, we've gotten the best version of Joe possible I think...so he took the step BUT I don't think the best version of Joe Milton is the best option for this system mainly because I think our style of play calling has changed to cater to Joe. But I am honestly shocked at how good Joe's numbers have been 65.3% 2283 passing yards 16 TDs 5 INTs, 301 rushing yards with 5 TDs
With 2 games left in the season he's on pace for 2740 passing yards, 25 total TDs and 360 rushing yards. That's a great season for Joe, that's not a great season for a QB in Heupel's offense...it's actually going to be the worst season for any starting QB in Josh's system since he's been a HC.
Hooker:
2022 - 3565 total yards 32 total TDs (missed 2 games)
2021 - 3565 total yards 36 total TDs (didn't start against Bowling Green)
Gabriel
2020 - 3739 total yards 34 total TDs
2019 - 3731 total yards 33 total TDs
McKenzie:
2018 - 2970 total yards 34 total TDs (only played 9 full games)
So did Joe step up and play much better? He did, he got better than he was in previous years...but he didn't step up enough to reach the level that a QB in this offense SHOULD be capable of especially in the TD department.