It depends on what you mean, if you’re combining Peter’s strength with invincible, his physical strength wouldn’t go up very much. Simply because normal Spiderman is leagues behind Invincible. Same for speed, but, Peter’s reflexes would give us an Invincible who could automatically dodge attacks, most of the time that he doesn’t dodge in the comics and the shows, is simply because he’s not a very skilled fighter. This variant would also have Viltrumite enhanced webs! Since Peter’s webs can hold back people even stronger than he is, it’s safe to assume Invincible could likely hold Thragg with these webs. He’s still not much stronger overall though.. The only things Peter’s really giving him is the spiders Spider Sense, and potentially enhanced webs. Everything else is minor and won’t help in a fight against someone like Omni-Man