bendy country roads shrouded by trees, very dark and visibility around corners was often very short, I dreaded the sound of an engine coming up behind me.
Why (dread)? You've got decent rear lights showing, you have said you're wearing a reflective upper garment, and the closing speed for a motor vehicle from behind is less. You will see the light from headlights behind, and I always look round: such movement aids conspicuity. Motor vehicles will slow and want to pass, and I'll look to help them (on bendy (narrow) country roads). On wider roads they just drive past, bit like in daytime.
Riding at night needs full attention (and potholes, leaves and gravel are the greater hazard imo).
You will see the loom of oncoming vehicle headlights approaching - I think on narrower roads it's actually safer than during the day, and I make sure my headlight returns the visibility compliment before switching to low power. Seeing your light the approaching driver will be expecting another (wider) vehicle and ease off/slow (depending on road width), and you'll pass one another safely.
Through the night rides:
Sterling to Lochgilphead (early on West Highlands 1000 - 2018) and
Daventry to Snaith (Easter Arrow 2019). More recently on PBP: Chateauneuf-en-Thymerai to Fougeres - 247km in 10
1/2 hours of Sunday's darkness: not much loneliness that night!