Why is the phone draining battery when the watch is separated?

My wife and I both have Samsung Note20 Ultra5G and Samsung Watch 6 Classic. - I have the 47mm and my wife has the 43mm watch. We also had E-Sims installed for the watches. - My previous Samsung watch used to last me 3 days, the new one was less than a day. - My wife's went from 2 days to less than a day as well. - Additionally we had to charge our phones several times during the day. - We noticed that when the watch was separated from the phone, the phone battery was discharged much faster. - We went back to Vodafone, and they said of course, it's because of the E-sim. This is garbage, the point of the E-sim on the watch is that you can leave your phone home and use the watch for phone calls. - Anyway, blaming poorly written software, we have removed the E-sims, my phone and watch has some sanity now, the watch lasts two days (still not 3). The problem is that my wife's phone still drains battery rapidly (goes from full charge to 10% in 2 hours) when the watch is separated from it. How can we fix it?