This is actually really really tough. On neutral ground, I give a slight majority, say 5.5/10 to Tyrant. In Shuma's realm, it's a bit more clear cut in favour of Shuma.
On neutral ground full powered Tyrant is going to completely destroy Shuma-Gorath. But in the Chaos Dimension Shuma-Gorath shouldn't be losing to Tyrant if Shuma has his head on straight and doesn't make stupid mistakes like he did against Doctor Strange.
Not Tyrant that's for sure. The guy got stomp and strunk by Galactus. SG would drain him dry. SG has a number of ways the can attack Tyrant, including in the astral plane.
Tyrant has been creeping around, hiding in the 616.
Shuma obliterated all comers in his universe and then spread out to influence and terrify others.
It is a "high level 616 bad guy" vs "the ruler of an entire dimension".
It would be another matter of there was evidence to show that Shuma's realm was an easy-take-over. But, he is all over the place, kicking a**, the 616. So, whomever he beat to take his universe, they were probably as tough as big boys in the 616.
And, I will end this by saying, once again, Tyrant may be a pain for Galactus, due to his affinity to Galactus tech, but he is NOT the biggest dog out there.