Repro:

1. Create a new project using the HDRP Scene Template
2. Open the default Scene "sampleScene.unity"
3. Generate lighting from Lighting Setting
4. Switch to the Baked Lightmap Scene View Mode

Note:

The Lightmap Exposure slider is presented in a range +/- 10ev. The default directional light is 100,000lux, which is approximate to direct sunlight. Typically, around 16evs (EV100) are needed to correctly expose daylight. The default range of the slider does not allow a good range of compensation for probably our most common lighting setup.

Now, yes, we can numerically change and "unlock" the exposure slider. However, I think we should provide more useful out-the-box defaults. Certainly it should cope well with daylight.

Expected:

The default min/max exposure should be 16evs as this is enough to cover the range of daylight values.