Receptacle Replacement in Older Home
The &quot;backstab&quot; connections normally only take 14 AWG wire. While a 15A circuit normally uses 14 AWG wire (since it is the smallest/cheapest size that meets code), you sometimes find a 15A circuit wired at least partly with 12 AWG wire (which can also be used for 20A circuits). That would easily explain why the backstabs don't work. But that's OK, because screw terminal connections are more reliable than backstabs.
Three things that are helpful with basic wiring are:

Non-contact tester - this lights up when there is line voltage present. It can have some false positives, but used properly it should not have any false negatives, so it is a very helpful safety tool. Does a non-contact tester light up next to any of the wires in this box?
3-light tester. Or as Harper calls it, &quot;Magic 8-ball&quot;. This is a plug-in tester that lights up for Hot, Neutral and Ground. It is not 100% reliable, but can help in diagnosing receptacle problems if you know how to use it. Does a 3-light tester show anything?
Multimeter. This can test all sorts of things. In this case, you are looking for ~ 120V between hot &amp; neutral and between hot &amp; ground and 0V between neutral &amp; ground.

The next thing to check is GFCI/AFCI. If your breaker is not just a standard &quot;flip the switch&quot; breaker, i.e., if it has TEST/RESET buttons, then you may need to reset the GFCI/AFCI functions after turning the breaker back on. Unlikely for a bedroom, but it is also possible another receptacle on the same circuit has a built-in GFCI that needs to be reset for this receptacle to work.
And last, but certainly not least, it is possible that another receptacle in this circuit has a loose connection. That gets time-consuming to diagnose, but basically comes down to checking each one and, even if it is working, seeing if there are any loose wires (especially backstabs) that affect power farther along the circuit.