Your description suits the House of Lords better, though is not wholly accurate.
The house of commons is the elected body and is by far the most powerful body of UK government. A select committee is a group of people (largely made up of members of the house of commons) with a specific goal in mind. In this case investigating the actions of Cambridge Analytica and Facebook. These findings will then be delivered to the House (of Commons) along with any recommendations. The government has a large influence as to who is on the select group, so normally listens to their advice.
When viewed in a certain light, maybe. But the monarch's hands are tied by parliament: while in theory the Queen may choose not to assent to a bill put before her, it's widely considered that freedom would be withdrawn if she actually tried to use it.
Much of what goes into the sausage-making that is the UK parliamentary system is there by custom, on the one hand because it would be legislatively expensive to modernise; on the other because no-one would ever agree on what to replace it with.
This is pretty much the case for any monarchy in europe these days.
In Belgium for instance, the monarch has to sign all legislation into law. For personal reasons, could not sign a abortion bill drafted by the belgium parlement.
Because denying to sign the bill directly would results in basically the end of the monarchy, he decided to "resign" for a day, the cabinet assumed his powers, the bill got signed, and he was reinstated again.[0]
The house of commons is the elected body and is by far the most powerful body of UK government. A select committee is a group of people (largely made up of members of the house of commons) with a specific goal in mind. In this case investigating the actions of Cambridge Analytica and Facebook. These findings will then be delivered to the House (of Commons) along with any recommendations. The government has a large influence as to who is on the select group, so normally listens to their advice.