Your IT has set up Conditional Access policies with a Sign-in Frequency set too low (it should really be labeled as a period, because it defines the time period that will occur before reauthentication is required). For regular users like all of you, forcing reauthentication that many times each day is excessive and just cruel on the users. They maybe thought it would make them super secure, but it only trains the users that MFA is an annoyance rather than an important security feature.

It’s a setting that can easily be changed, so make some noise and see if you can get some feedback passed through your org structure to IT.