When you read Tertullian it sounds more like an "I'm arguing from Luke which Marcion falsified to prove that even Marcion's god is the creator" that it sounds like Tertullian has the Marcionite text in front of him. Let's take the example of the apparent citation from Matthew in chapter 7:
7. [Luke 4: 31-7.] Marcion premises that in the fifteenth year of the principate of Tiberius he came down into Capernaum, a city of Galilee—from the Creator's heaven, of course, into which he had first come down out of his own.1 Did not then due order demand that it should first be explained how he came down from his own heaven into the Creator's? For why should I not pass censure on such matters as do not satisfy the claims of orderly narrative, <but let it> always tail off in falsehood? So let us ask once for all a question I have already discussed elsewhere, whether, while coming down through the Creator's territory and in opposition to him, he could have expected the Creator to let him in, and allow him to pass on from thence into the earth, which no less is the Creator's. Next however, admitting that he came down, I demand to know the rest of the order of that descent. It is no matter if somewhere the word 'appeared' is used. 'Appear' suggests a sudden and unexpected sight, <by one> who at some instant has cast his eyes on a thing which has at that instant appeared. To have come down, however—when that takes place the fact is in view and comes beneath the eye: it also puts the event into sequence, and enforces the inquiry in what sort of aspect, in what sort of array, with how much speed or moderation, as also at what time of day, or of night, he came down: and besides that, who saw him coming down, who reported it, and who gave assurance of a fact not easily credible even to him who gives assurance. It is quite wrong in fact, that Romulus should have had Proculus to vouch for his ascent into heaven,3 yet that Christ should not have provided himself with a reporter of his god's descent from heaven—though that one must have gone up by the same ladder of lies by which this one came down. Also what had he to do with Galilee, if he was not the Creator's Christ, for whom that province was predestined <as the place> for him to enter on his preaching? Also what had he to do with Galilee, if he was not the Creator's Christ, for whom that province was predestined <as the place> for him to enter on his preaching? For Isaiah says: Drink this first, do it quickly, province of Zebulon and land of Naphtali, and ye others who <dwell between> the sea-coast and Jordan, Galilee of the gentiles, ye people who sit in darkness, behold a great light: ye who inhabit the land, sitting in the shadow of death, a light has arisen upon you.a It is indeed to the good that Marcion's god too should be cited as one who gives light to the gentiles, for so there was the greater need for him to come down from heaven—though, if so, he ought to have come down into Pontus rather than Galilee.
The Western text of Luke 4:31
Following the notice of Jesus’ arrival in Capernaum, a city of Galilee, D adds an additional phrase from gospel-parallels:
την παραθαλασσιον εν οριοις Ζαβουλων και Νεφθαλιμ (“which is upon the sea-coast within the borders of Zabulon and Nephthalim”)
The reading, from Matt. 4:13, differs only slightly in reading τὴν παραθαλασσίαν.
I find this very difficult to explain as being anything other than someone using a Western text of Luke. I see no evidence of a Marcionite text present here. So the "He came down to Capernaum" and the reference to Isaiah in Against Marcion is explained by the Western text of Luke. The only way Against Marcion makes any sense as if the person writing the account was arguing from a text that read as Bezae:
"And he went down to Capernaum, a city of Galilee situated beside the sea in the territory of Zebulun and Naphtali, and he was teaching them on the Sabbath."
Is anyone seriously telling me that the Marcionite gospel read:
"And he went down to Capernaum, a city of Galilee situated beside the sea in the territory of Zebulun and Naphtali, and he was teaching them on the Sabbath."
Then what prompts Against Marcion to write, immediately after its take on "he came down to Capernaum" the words:
Also what had he to do with Galilee, if he was not the Creator's Christ, for whom that province was predestined <as the place> for him to enter on his preaching? For Isaiah says: Drink this first, do it quickly, province of Zebulon and land of Naphtali, and ye others who <dwell between> the sea-coast and Jordan, Galilee of the gentiles, ye people who sit in darkness, behold a great light: ye who inhabit the land, sitting in the shadow of death, a light has arisen upon you.a It is indeed to the good that Marcion's god too should be cited as one who gives light to the gentiles, for so there was the greater need for him to come down from heaven—though, if so, he ought to have come down into Pontus rather than Galilee.
Clearly the person saw "And he went down to Capernaum, a city of Galilee situated beside the sea in the territory of Zebulun and Naphtali" and connected it with the prophesy in Isaiah as we read in Matthew. It is complete bullshit to assume that the person was using Marcion's gospel.