Trying to install arch with jumpdrive, but jumpdrive isn't booting

[wibble]

Code:

of=/dev/sda2

should be

Code:

of=/dev/sda

The correct information was written to the microSD card, that was simply sda # stacking up from previous usb mountings.

Jumpdrive is safely installed on the microSD card, the output(which could've prevented your misunderstanding) is the following:
39522816 bytes (40 MB, 38 MiB) copied, 4 s, 9.9 MB/s
83968+0 records in
83968+0 records out
42991616 bytes (43 MB, 41 MiB) copied, 5.0879 s, 8.4 MB/s

This indicates that it was written to a drive, while the only drive attached to any sda was the microSD card

tl:dr - still looking for suggestions on how to successfully install arch linux on my pinephone

I believe it's you that is misunderstanding. If you wrote to /dev/sda2 you wrote to the second partition on device /dev/sda, not to the raw device, so the data was written to the wrong place on the device and won't be bootable.