I’m currently working on a more complex project that uses double sided assembly (and a weird USB-C connector). To practice these things a little, I ordered some low cost boards to get used to that connector and explore double sided reflow (which seems easier than I expected).
For those who are interested, this is a reference design from framework computer for their expansion card system. It can be programmed with circuitpython or Arduino and utilises a SAMD21 microcontroller.
I was kind of afraid of SMD things in general a long time but I discovered they are (up to a certain size, 0603 is still okay for hand assembly if you’re patient) comfortable to work with. Even QFN packages are okay if you have access to a hot-air station. I did actually order an BGA sensor out of curiosity along with other things, looked at it and was like “hahaha, thanks, I probably better don’t design that thing into my circuit” (I think it’s a 5-WLCSP package).