"I just came across a fairly new hyper-thyroid medicine for cats called "Thyronorm". Seems it's sold in UK, but maybe it can be shipped to US. https://www.petforums.co.uk/threads/new-oral-liquid-for-hyperthyroidism.430642/ I haven't checked.

Other detailed information: https://www.vetclick.com/news/thyronorms-liquid-formula-improves-compliance-in-cats-with-hyperthyroidism-p4759.php

Feline hyperthyroid specialist, Dr Sarah Caney, says Thyronorm® Oral Solution for Cats, with its breakthrough liquid solution, is revolutionising the compliance levels of lifelong hyperthyroidism treatment.
“Due to the disease affecting a cat’s behaviour and making them irritable and anxious, it can make them difficult to medicate,” says Dr Caney.

“Cats are often a challenge to dose with owners battling with traditional tablet form medication, so the feedback is that a treatment that is popular with cats, and is easily accepted, such as Thyronorm, is ultimately making owners’ lives easier.”