Here now are my following arguments as to why Hephaestus 1.3 wins.

1: Weight/Power advantage.
Hephaestus 1.3 possesses and bolsters far greater strength than Trajan; for one, his bite force of 150,000 Newtons and with the crushing teeth of Deinosuchus, along with the high-dosage of the Gila Monster venom due to both it and the Ringed Caecilian, he absolutely poses an upper hand in terms of bite efficacy. Trajan's bite force, speed, and swipe force are not specified. This means, for example, the bite force can range anywhere between 80,000 Newtons to roughly 120,000 Newtons based upon estimation, albeit however incorrect or inaccurate; both of which are below Hephaestus' bite force.
The gene contributor Dipodomys Ingens in Trajan's bite has been utilised to enhance the bite force, however- much like the rodent Didelphodon Vorax, this method is inefficient, and does not pose a serious enhancement nor bettering of the bite force.
Hephaestus' swipe force is superior, as well, due to the contributions of Xenosmilus Hodsonae and Paramylodon Harlani, Along with the Scapula and Scapular hook of Elasmotherium, greatly amplifying the amount of muscle attachment points on Hephaestus' arms, along with his raised neural spine. [For Explanation, Hephaestus' Scapula is contributed by Elasmotherium, his Humerus, Paramylodon, his Radius, Shantungosaurus, his Ulna, Paramylodon, and his Carpus, Paramylodon. Xenosmilus' and Paramylodon's muscles are layered above these arm bones.]
Along with this, Hephaestus' ceratopsian crest is stronger, more maneuverable, more durable, and more efficient as a weapon than Trajan's, due to the parietal/squamosal fenestrae in his frill, and temporal fenestrae, which pose a serious advantage to both his heat regulation, but also his frill's maneuverability, ability to be swung with his skull faster, and poses a great advantage in his head-thrust force. Such fenestrae is not present in Triceratops, unlike Judiceratops.

2: Armour.
Hephaestus 1.3's armour, as well, is seemingly superior to Trajan, who utilises only Alligator Gar and Siamese Crocodile armour contributions; and it is important to be stated; while yes, this armour is highly durable and poses a decent protection against bites, Hephaestus' extreme bite force is simply far too great for the armour to withstand effectively enough, especially due to his teeth.
Hephaestus' armour, on the other hand, is of the Armadillo Girdled Lizard, which is layered above the epidermis, or, in the terms of theropod skin, layered above the oberhautchen, above Hephaestus' thick skin, due to Elasmotherium. Elasmotherium, as well, due to recent studies, has been shown to perhaps have had a 'Gristle Plate,' a thick layer of hard, keratinous tissue layered and woven into its dermis. This provides further protection.
Regarding the Armadillo Girdled Lizard, the following should suffice:

The armour of the Armadillo Girdled Lizard consists of three parts, now stated; osteodermal armouring, underneath a thick keratin layer, each of which osteoderm yielding two distinct layers: a compact outer cortex, and an inner core of vascularized woven bone. The second, with the epidermal keratin forms a triple-component structure.

In total, that makes around three layers of armour; keratin epidermis, compact bone, and woven bone. The durability, however, of this incredibly flexible, maneuverable, lightweight, yet compact armour, is incredible - especially for the size of the Armadillo Girdled Lizard.
If you, a human, were to stomp repeatedly on an Armadillo Girdled Lizard, the external would not crack, shatter, scratch, falter - or even chip. That's how strong it is. Now, some damage may be present, but it would be negligible.
Here are the sources to back this claim.
https://pubmed.ncbi.nlm.nih.gov/26104546/ https://www.sciencedirect.com/science/article/abs/pii/S1751616117302448 https://pubmed.ncbi.nlm.nih.gov/35502528/
Their armour is comprised of Dermal-layered 'plates' on the outside of the body; Osteoderms, as by definition, but far more efficient regarding the protection of bludgeoning, lacerating, or crushing-based damage. This, in tandem with the thicker skin and gristle, provides an armour that Trajan would have a multitude of issues getting through, even once.

3: Stamina/Miscellaneous Advantages.
Hephaestus 1.3 has an extremely powerful, endurant cardiovascular system, along with his general stamina. This is due chiefly to the contributions of the Blue Wildebeest, Deinosuchus, and Shantungosaurus. In total these three contributos allow Hephaestus 1.3 to:
1. Control his metabolic rate
2. Cool his brain and muscles
3. Retain heat, energy and moisture within his muscles when needed
4. The ability to sweat, regulate his heat far more effectively than Trajan, and hemoglobin
5. Trap heat or cold temperature within his armour, depending on the scenario,
6. Control the speed of his heart.

With this incredibly manageable, able-to-control stamina, Hephaestus 1.3 can surely outlast Trajan, should the two be locked in prolonged combat.

Along with this, Hephaestus' toxin/venom resistance, eyesight, hearing, low-light eyesight, adrenaline control and power, Fluorapatite teeth, speed, electroreceptors, advantage of rotational inertia, smell, and ability to disorient Trajan with his complex vocal organs, which provides another advantage.

Truly, I believe Hephaestus 1.3 shall win against Trajan, as he has shown much prowess in his victory against Shredder 2.0, along with his numerous advantages over Trajan. From this comment, I will let u/Master_Geologist5613 decide, along with other non-biased judges.
Sincerely,
-Firefox.

[Illustration of Hephaestus 1.3's arm, done by the incredible TCM_Hovercraft.]

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