Season 2 added around 2.5-3 million more viewers each week, with the DVR ratings jumping a bit in the 18-49 demo, although still staying in the 0.7-0.9 region.
It’s not always clear what networks take into account with the renewal or cancellation decisions.
It’s rarely just one thing — cast/writer/producer contracts, cost to produce the show, what else is on the schedule, fan outcry, etc. But if the Fox suits check DVR numbers, for people who watch the show within a week of airing, The Orville seems to do fairly well.