Many PCB services offer SMD assembly as well, though the pricing is quite high for prototypes. PCBWay e.g. quotes over 300 USD for a single board with 2400 parts, though that price goes down quickly when ordering more (e.g. when ordering 50 they will only charge 20 USD per board).
Do you know of a tutorial on how to do assembly with KiCAD/JLCPCB? I've designed a few PCBs and tried to do assembly once, but IIRC my biggest problem was figuring out which parts they had that I could use and how to send them the info.
I did it for a board and it turned out pretty good. Make sure there's a pin 1 marker on your footprints so that in the preview (which they show in the submission process) you can make sure the parts are all aligned (and they will double check as well).
Basic parts are free to use at just the assembly cost. Extended parts add an extra $3 processing per bom item (not per part). Basically as far as I can tell their parts are the same as LCSC.com.
Also, Phil's lab has a long video on assembly from start to finish from Kicad to JLCPCB
It does this from a field on each part in the schematic called "JLC" containing the part number. The only thing I'm unsure of is whether the "footprint" column needs to be edited manually later, though.
Is there anyone here that would assemble something like this for cheaper? I don't have a reflow station but am making something similar and would pay someone to do a prototype (hopefully less than $2400). Based in Los Angeles.