A not-so-intuitive step to advancing Alissa's route requires you to tell Cassie to change clothes several times in a row.
Best advice I can give for the giant meat abomination is to just... hit it really hard...
If you save up 2k credits for a condo and 1k credits for a lifetime membership at the gym, you'll have an unlimited means of training up your strength, nimble, and resistance. For our main protagonist, eating is optional lol
But of course, you can bring milk and stamina drinks with you to make the stats grinding less tedious.