It’s always better to have the earliest hardware revision possible, but there’s no guarantee an exploit will ever be found even on lower revisions. On the switch 1 we had an unpatchable hardware issue in the first generation of the hardware, but this really was a fluke (and the fault of NVIDIA, not Nintendo). In my opinion the chance for the same thing to happen again are very low, but still higher on the launch units than in later revisions.
I think there are really only two ways to go about this: either you buy a switch 2 now and leave it in the box until a softmod comes out (if one ever does come out), or a mod chip; or you buy a switch 2, update it and play with it, just making sure to put it in flight mode before putting it on the shelf if you ever get tired of it, so if a softmod does come along, your firmware stays as low as possible.