LineageOS, please support my new device! Pretty please with cherries on top!
tl;dr It’s up to you.
Sorry to let you down, but LineageOS device support has nothing to do with the number of device requests received (or the number of cherries added on top, for that matter). The folks who maintain devices for LineageOS choose devices that interest them. Remember, these are regular people enjoying a hobby. LineageOS is not a corporation with employees. So, step one, purge your mind of the mentality that developers are sitting around waiting for advice about what to work on next.
There’s more to this story, though. Be wary of individuals who tout, “I bought a new device! It will therefore have fancy AOSP soon!” All too often, these are folks who underestimate the difficulty of bringing AOSP to a device. Even skilled maintainers cannot predict all the hurdles they will face in bring-up. Someone who says “soon” is someone who hasn’t experienced the utter joy of having a device 99% finished, but one last function (e.g. fingerprint reader, HDR, encryption) takes months to get working.
Perhaps the only somewhat reliable indicator of whether a device may be officially supported is when a developer’s hard work in bringing-up a device is forked over to github.com/LineageOS. Notice, this is after a developer (or regular Joe, see below) puts in the time and effort to get LineageOS running reliably. There’s still no guarantee of official support at this point; the device needs to meet a number of quality control checklist items and the developer needs to agree to maintain the device over time. But, there’s at least a decent chance.
Ok, so if nobody is making headway on your device, where do you go from here? Consider that the majority of the device maintainers for LineageOS have significantly different day jobs than Android device maintenance (or even programming, for that matter). If you are passionate enough about getting LineageOS up and running on your device, you can make it happen. Start easy; buy an old, but well supported device and try compiling your first ROM. Once you’re running software you compiled yourself, start investigating the device configuration files. Tweak, and then tweak some more. Eventually, see what you’re able to accomplish on your device of interest!