This sounds really great. I also left my early 2015 13" MBP at the Apple Store Munich. The genius bar checked the computer, the battery resulted in problematic condition, he told me that this is not a "must" to do, however I proceeded.
Until 09.12.2021, hopefully, the top case will be replaced including a new keyboard, a new trackpad, a new battery as well. I hope I can also be satisfied like you, after the process is done.
In addition, have you noticed any improve or quality difference between the old and the new battery? Did it make any improvement in terms of battery hours etc?