which beetles are these?

Good evening,
I found two different bugs in our house, south of the uk, humid.
The small one is really difficult to see and very tiny, almost invisible if you do not look for it especially. I found it in old games (cardboard box), in a north-facing room which smells mouldy.
The other one, the darker one, seems to live in different places, I found it attached to the bathroom door, once I saw it in our kitchen shelves (which contain spices, and flour, cooking things), also on the floor.
Both are tiny as measured.
Now I would like to know a few things:
are they the same? the first one seems also to develop a darker back side.
what do they eat? wood? clothes? fungus? hair/keratin? everything?
how can I get rid of them?
I would very much appreciate your help...

how can I upload pictures?