Dimmer Switch in hallway?

I have two switches in my hallway, which control the lights in the hallway. When I turn a switch ON, it turns on both lights. I can turn OFF lights using either switch.

[Switch on/off] ---[Light 1]---[Light 2]---[Switch on/off]

The problem is at night, because the hallway light gets into the bedroom when I open the door and it disturbs my partners sleep. She is a light sleeper.

Is there a way to change one of the switches to a dimmer switch?

I did consider a low 25 watt bulb, which is fine for nighttime, but during day time, it does not provide enough light as the hallway has no windows.

Is there any solution? Is there a switch which behaves like a normal on-off switch, but can override it to be a dimmer, when needed?

Sounds like a standard 2-way switching arrangement. You can replace one of the existing switches with a dimmer which includes a 2-way switch, such as this:

https://www.tlc-direct.co.uk/Products/VL12.html

(Make sure the one you get is 2-way and of suitable rating for your existing lights.)

Do bear in mind though that when you turn the lights on using the on/off switch they will be at whatever brightness the dimmer happens to be set to, and if that is not right you'll have to go to the dimmer to change it.

You might be better off with a master/slave dimmer pair, but please take a bit of time to learn how 2-way switching works, and to find how yours is wired, before plunging in making changes.