I can confirm google chrome is a big culprit, I guess it's the syncing in the background that it does. I have an urge to delete it as I use edge as well. But I also love my autofill and that's why I keep it as my Ultra still lasts me a day or 2 days with moderate use.
Yea I couldn't not use Google chrome unfortunately. I do admit that I regularly use my phone. I'm not wanting it to last 2 or 3 days but I High end smart phone, I would expect at least the full day with normal usage. Maybe even a charge towards the end of the day but yesterday at 1pm in afternoon I was down to 20%
I feel lot of apps like Facebook and chrome are not playing nice with the s21, need optimisation both from Samsung and the app developer. Playing video in chrome will eat through your battery as well. Try YouTube instead, I have to check if it makes a difference.