Aligning stencil and board with pins works really well (I know this is quite common but it's the first time I tried this, and also my first boards and stencil from JLC):
All went well (unfortunately?) for the first one:
This board was done on Jan 17th 2022, reflow started at 21:03 (almost full moon).
And it works with a coin cell on the bottom and also with USB supply: