How can I wire this switched GFCI combo outlet with two neutrals and two hot wires?
If you look carefully at your old outlet, you’ll see that there is embossed on the outlet “line” near one pair and “load” near the other.
The line wires are the power feed and the load wires run onto more outlet and/or lights that are also protected by the GFCI.
If you want, you can connect the load wires to the load terminals of the new GFCI. However, then whatever is there will also be controlled by the switch.
To avoid controlling those by the switch, you’ll need to connect the two pairs together. However, that will remove the protection from whatever is downstream and you’ll need to add one or more additional GFCIs to replace that protection.
You may want the trip off the current GFCI to see what else loses power. It could be another bathroom or even garage or outdoor outlets.