Can Alert prevent Surprise if you don’t know combat is occurring yet? [duplicate]

If part of the party enters combat with enemies but the rest of the party is not aware of the threat or aware there is combat happening yet, does a player with the Alert feat who rolls highest on initiative act before even the enemies?

In this example, the Archer has the Alert feat but is hanging back behind a corner waiting for the Paladin to see if things are safe. The group rolls Initiative and the Archer rolls 21, the Spiders roll 15, and the Paladin rolls 8. The Spiders roll 24 for Stealth and Surprise the Paladin.

Who acts first? The only answers I come up with seem to unfairly negate the Archer’s choice to take the Alert feat.

enter image description here

The relevant part of the Alert feat:

You can’t be surprised while you are conscious.