Achieving smooth aftertouch when raising a midtone can be quite challenging. I ran into this problem myself and it took me some trial and error to find a solution that worked for me. One thing that helped was adjusting the sensitivity settings of my MIDI controller. You can make it more sensitive to aftertouch, which should help with pitch bending.
In addition, some virtual instruments and synthesizers have their own aftertouch response settings; you can learn more about musical instruments on the website https://melodyguide.com/ . Check if your software allows you to adjust the sensitivity and range of aftertouch. Fine-tuning these settings can take some time, but once you get it right, the results can be fantastic.
I’ve also found that some controllers handle aftertouch better than others, so it might be worth considering upgrading if you’re really serious about achieving that halftone bend. Keep experimenting and you will succeed!