Yep, mill, or if you don't need a large mill, then a mini mill instead.

Hence most drill presses have too much run out to start with.  Even if you square to run a reamer after piloting, you will still be over sized since you have to account for the run out of not only the spindle, but the chuck as well.

Also, when you are spotting a channel to begin with, better to have the piece clamped solid and square to the spindle so the channel will be square to the line you are piloting to begin with  and work the axis's to align for the needed channel.  With a drill press, you playing the clamping movement or hand holding game, and bank that your not going to end up with the channel where it needs to be isntead.

To add, it not hard to DRO a mini mill, and a hell of lot easy to tram the head to the table for all the axis's.  On a drill press, very, every seldom is the table even close to be trammed with the head, and the first time you move the table, could be off in the other direction instead.

To be blunt, drill press is fine for drilling over size channels for through bolt and that is about it.