想法是对的，但是写的不够polished，我提供一个version供参考

I would like to sincerely thank XXX for taking the time to introduce this new function to the team which I should have done much earlier. As always, I really appreciate the support that XXX has provided during the development process. I would also appreciate any comments and suggestions from anyone so that I can continue to make it better.

这样，你的lead的地位就很清楚了，他也得到了支持者的credit，显示了你的功劳，同时你还显得很谦虚很positive。。。。