How about this:

- 1 pass through the router with a 3/8" straight cutter
- 2 passes through the table saw with the blade tilted to your angle
(stock turned end-to-end for 2nd pass)

If grove is not centered on the stock, the 2nd saw pass would require
moving the fence. Or better, having an offset piece clamped to the fence.

No bit changes, or set up changes except for the possible saw fence offset.

Bob