When coaches talk about an all-round striker, they usually mean the things that keep the team functioning when you are not finishing a chance.
That can include holding the ball long enough for support to arrive, linking with midfield, making runs that create space for someone else, pressing with the team, competing for second balls and recognising when the team needs you to stay high rather than come towards the ball.
You do not need to become brilliant at every part immediately. Ask your manager which two areas he feels are currently costing you starts.
For example, if your finishing is already trusted but the team struggles to get up the pitch when you play, your next focus may be securing the first pass into you. If the press breaks down around you, it may be your defensive movement.
'All-round' should become specific behaviours you can work on, not a vague judgement.
