OP-
If you just don't want to pay a shop, I really don't know any decent work-around or DIY for derailleur hanger or dropout alignment.
If you ride MTB a fair amount (and I mean offroad), the Park DAG is the only way to go. I have one and it has certainly paid for itself in correcting the almost guaranteed occasional misalignment of the hanger for the inevitable crashes.
Dropout alignment is a much rarer need. If you really just love having specialized tools, then go ahead and treat yourself. I have rarely needed one and just pay the shop to do it.
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"I tell you, We are here on earth to fart around, and don't let anybody tell you any different." - Kurt Vonnegut jr.