Everyone knows it's bullshit, but this kind of toxic/fake positivity is demanded, and weirdly, it works even though everyone knows it's fake.
Sales people ringing a bell in the office when they make a sale is traditional in certain sales environments. When I worked in radio, the sales people did it. I've seen food truck operators and baristas do it when someone tips.
It's related to the expression "ringing your own bell," which means to be shamelessly boastful.
I've seen exactly this in the Technology department at one of my employers... When the sprints ended the teams that shipped an increment would gather around the bell and each take a turn ringing it while everyone cheered them on. Sprint symposiums happened the following week.
I worked on a project with them that impacted our "shadow IT" team and received an email marked as mandatory attendance required at a meeting. It turns out the meeting involved all 1000 people in the office clapping and cheering for the teams that were involved in the project.
I have no idea what they are doing now it's all remote.