When Google started pre-announcing broad core algorithm updates back in 2019, the SEO community rejoiced. However, Google makes changes every day in their algorithm and thousands every year. Broad core algorithm updates happen multiple times a year, but there are algorithm updates that happen more frequently.
Their effects are unfelt at times but often they make enough noise to be noticed by the SEO community but not big enough to be announced by Google. These are called unconfirmed Google Algorithm updates.