I have the Ultra 2. I just charge it while I'm showering every day. Sometimes I'm slow and I get to 100%, other times only 90%. When I wake up in the morning, I always have more than 70% left.
I don't have any particular power savings enabled. I have the always-on display turned on, and keep the watch "alive" for 70s instead of 2s. I work out for about 45 minutes a day without any power-saving settings. I interact with the display somewhat regularly (always checking on my stand credit).
Basically, you will not have any battery life problems.
Double Tap works for me. I remember to use it approximately 1 time out of every 100, though. Reading the comments is useful, though. I didn't know it could dismiss timers. I might remember to try next time!