Just my two cents but I just don't think this is something to stress over whatsoever.
Use your smartphone as you need to use it: calling, texting, web surfing, photos and videos, games, music, GPS directions, work emails, social media, smart home and voice controls, financial apps. At least those are what I use it for but I'm sure others have other usages. When it needs a charge I plug it in. Don;t even worry about it. Just use it as you need for these things you want and need. With optimized charging enabled, it's going to know what your general charging patterns are and work to keep it from staying at 100% for extended times. This alone will get good solid life out of it. Batteries in smartphones are now very good. My GF has a 6+ and never worried about how she charged it. When it needed a charge she charged it. It still gets mostly full day of modest usage.
On another note, on all my trade ins with Apple I've never seen them ask about the battery metric. Physical appearance (no cracks etc) and general functionality are all they care about. I've always assumed prior to resale they replace the battery.
Your phone should be an enhancement not a worry. Peace...