We certainly need a refresh in our attack. I tend to agree with lorddulaarsenal that starting clean from an attacking perspective would be the best way to do it but I just can't see us selling Gyokeres one year after we bought him (even though its what I would do) or Havertz due to his versatility. Also given that it's a World Cup summer, I think there will be less movement than we would need to do a full refresh.
I think you keep one of Gyokeres/Havertz (I'd lean toward Kai since I think he's a better footballer but it depends entirely on if he can stay healthy during this run in), and then bring in Alvarez as our main 9, with VG/KH providing depth along with Merino in a pinch. Alvarez can also play off the left if we want but I'd like him to be our focal point.
Sell Trossard and Jesus and bring in a top dribbling and playmaking threat on the left. Both of them have a similar profile and I think that profile is valuable as a versatile forward that is technical. Yildiz would be my dream fit here but I don't see him leaving. Diomande really looks special to me but he won't be cheap. The Belgian at Ajax, Godts, looks talented as well but not sure if he would be able to come into the EPL and hit the ground running. I also am a fan of N'Diaye but not as our primary LW so I'd only be interested in him if we sold Martinelli and upgraded.
I like Martinelli and don't necessarily think we should sell him but I'd be very interested if the right offer came in. If we did sell him, it would be essential that he is replaced by someone who has elite pace as it's something the squad lacks aside from Gabi and Madueke. I go back and forth on Gordon but I really think he's an upgrade to Martinelli - he has incredible off the ball movement, has shown he can score big goals and isn't shy to take on responsibility and also works his butt off defensively. Bahoya would be another option but he's raw.
Personally, I would feel pretty good if we went into next year with the following attack:
LW: Gordon, N'Diaye, Madueke
ST: Alvarez, Havertz/Gyokeres, Merino
RW: Saka, Madueke, Dowman