There are several passive, soundhole mounted pickups that should work for you.
Fishman NeoD-02
Seymour Duncan woody
DiMarzio.
I'm guessing you do not want a permanent installation. Given that, you will need to deal with the chord dangling down from the sound hole. A feature I hated. I also found the tone (Seymour Duncan) a bit "electric", which is a characteristic of many of the humbucker soundhole mounted pickups. Many of the single coil style will have the distinctive hum. Of the bunch above the Fishman Neo D02 sounds the most natural to me.
If you don't mind drilling a hole for the end pin jack and still want a soundhole mounted pickup, then the LR Baggs M1 is a good option. Sounds very natural, has a volume control (needs a battery). But, if you're willing to drill a hole then I'd suggect the K&K western/mini. You can also do it with a vintage style jack, that means you do not need to drill a 1/2" hole, but can use the smaller strap button hole. This way the guitar retains the original appearance and can be returned to original specs, although removing the internal bridgeplate mounted pickups is a real challenge.