When you say not seeing much change what do you mean? Did your FTP increase, and do you find the steady state stuff slightly easier after these plans? if you do and the group has remained at same speed you should find you’re fresher for the sudden changes. ie. its a lower % of FTP or are you now pushing at the front more etc so just adding to stress?
Sweet spot Base 2 is a good mix in the low/mid plans. They are a pre build rounded plan which from personal experience and other posts on improvements give good results. Sustained build should have helped though, both with the V02 workouts and slightly greater than FTP/ or over under workouts. If not how closely did you follow the plan and have you got a Power meter and recently tested? Did you struggle with the workouts? most people find Build tough if FTP is set right
A V02 block is a good alternative if its relatively short durations you want to improve, to push up the ability to hold high numbers and might change up your intensity and give the body something new to stop plateaus. if all you are doing is long rides no focus then you need to put in a wider range of intervals and give 2 structured and higher intensity rides per week a go and stick with for 4-8 weeks.
PS Wheeler?