Lukaku's biggest problem is that he's not executing a lot. He has a high conversion rate because he doesn't take his chances. He wants to be 100% certain that it will go on target to make the shot. And even then, it's not really that high since most of them are usually high quality chances. He has a good first time shot which is a direct contrast of his awful first touch, but explicable since a first shot can be overpowered whilst a first touch will feel like a bad pass instead. But for a first time shot to work, he needs to get away from defenders or be forgotten by them. Which won't happen very often and he has to be ready for the few moments it does because that's his highest chances to get a goal. Still feels like PKs and (rebound) tap ins will be his major source of scoring.
He's capable of providing space for teammates occassonally (ie dummies or help with one-twos), but that usually comes when we are counter attacking and mostly vs inferior sides. That's not going to be a very popular situation for us. If the offense clicks then maybe this will liberate us more moving up front.
Our most dangerous players offensively so far are Politano, Sensi and Lautaro. Politano could have scored like 4 goals so far (one annulled for Lukaku's lack of awareness, a couple hit the post and so on...)
If we have more great crosses (like the ones from Barella and Godin, plus Sensi who can pull it off) and bad defensive hiccups in favor (Romagnoli's man marking and Lecce's lack of offisde trap) then we can see him having a relatively good year. But so far it seems like opposition, with the exception of Slavia Praha, fears him due to his imposing stature more than anything. Which is good for us and hopefully he manages to convert quite a few to gain confidence going further into the season before the defences start realizing that he has some major weaknesses they can take advantage of.
Not very worried about him vs Lazio, but would prefer him next to Politano or Sanchez. I feel that Lautaro + Sanchez/Politano is going to be our best duo but there's no way you can bench Lukaku and he even has the goals thus far to show for.