There are a few things to be concerned about this matchup.
There are three certainties in life, taxes, death, and Gamrot getting knocked down by his opponent. Almost every fight he gets dropped. Even Rda old decrepit ass dropped him. He looked unflattering there. Gamrot is known for a habit of having average ctrl time. And his subs are not on par with Islam, when it comes to sub rating.
This could easily go like the Guram fight, and although some felt he should have won, it was close, and i've never seen anyone ground Hooker for long times. Jason Knight was the last guy with 4 mins of ctrl in 2016, and he's a guy that had a bunch of subs, and tried to sub hooker with no success.
This seems to be a dog or pass for me. Gamrot has always been favorited against fighters who have average wrestling and scrambles, i don't put Hooker in this category, he's out grappled quite a few guys with his own grappling and has an 80% tdd. Hooker also has a ko power advantage, better standup, durability. This comes down to how good Gamrot is at keeping Hooker guessing and being able to land his strikes and shoot takedowns to then clinch Hooker against the cage and put on a high stamina pace. Similar to how Merab and Umar fight.
This has a lot of the same elements as Sandhagen/Umar fight, Hooker biggest flaws are his koes consist of kicks and not heavy punches. And while he can stuff takedowns, his worst matchup will undoubtably be a grappler, it just depends rather Gamrot can impose his grappling, which is not impossible.