It's threadless, no stem, 1 1/8 If you have a 2.0 you need a 1" to 1 1/8 stem
QUILL STEM ADAPTER STEM HANDLEBARS
MY STEM: freneci 22.2 Stem 28.6mm Bike Handlebar Stems for, Road Bike, BMX https://www.amazon.com/dp/B08KP5Y26C/ref=cm_sw_r_cp_api_i_PJ0XWF24KE3JV4JT085C?_encoding=UTF8&psc=1
MY ADAPTER: UPANBIKE Road Mountain Bike Bicycle Stem Riser Adapter 1 1/8" φ22.2mm 25.4mm*150mm https://www.amazon.com/dp/B071J12DXW/ref=cm_sw_r_cp_api_i_CKH7BC4KX9MYPZ159KF0?_encoding=UTF8&psc=1
MY HANDLEBARS: Eastern Bikes BMX Handlebars Throttle 10.0" Gloss Black https://www.amazon.com/dp/B01N6NJS0H/ref=cm_sw_r_cp_api_i_MB56QEDW1JAGKJCTJREC?_encoding=UTF8&psc=1
My personal opinion I would look into a better stem and more durable, I bought this cause it was cheap but I do plan on buying a higher quality stem.
The quill, the quill is great and I have no issues with at all so that quill is 100% necessary
Now for the handlebars, I would be careful and definitely look into a few before buying one. Before my handlebar upgrade I rode my bike the handlebars and the lowest height and my same thing with my seat as I’m a short guy. The comfortability with that adjustment was perfect for me. So although my new handlebars are sitting at the perfect height, they are about wider than the factory handlebars, which makes them a bit uncomfortable as my handles are much more apart than I want them to be.
So like I said, just do research on your handlebars. Measure out where your current height is from your quill to the top of your handlebars and and the width of them and try to find handlebars, good quality handlebars too I may add, that much up with your current setup and that would best fit you.