UA User Report is almost double the GA4' report

I've been tracking my website with a GA4 property for a while now, and with enough data to compare to the UA property, I noticed that UA users report is almost double the GA4 report. I've search about this and founded that GA4 is more focused on events than sessions, but even when I look up on Event tab, the event count is not as high either. I've also seen other people with the same problem as me but never found the solution.