I joined on to the team in 2018 and they were already using WordPress. Not sure of the specific time frame, but I think they made the switch sometime around 2015, but don’t quote me on that.
I think everyone likes it, although we’re still using the classic editor for most of the sites. It’s a multisite installation, so there are a lot of non-technical users that maintain content, though they have to go through an application process and training.
For freelance work, right now it’s main been just subcontracting work with a family friend and doing customizations for sports plugin I built a few years ago. Still trying to figure out the marketing stuff (fun times for an introvert).