It's not an Apple issue; if it is software, it is a third party app software issue.
First, 5G radios use more power than older chips do. Do an Internet search and you will see it's also true for phones from other vendors.
Here's the Wall Street Journal on the subject:
5G Drains Your iPhone’s Battery. Here’s What You Can Do About It.
If you prefer:
Samsung: Samsung Battery Drains Quickly on 5G Service
Second, which older iPhones? Only iPhone 12 and 13 had 5G support and battery life is actually better with the iPhone 14.
Finally, if the battery statistics show a particular app is using most of the battery, that app is at fault or you just have to realize it will use a lot of power. Map/GPS apps will always use a lot of power because they are constantly checking where you are, how much you've moved and redrawing maps and usually retrieving traffic data and other information from the Internet.
In essence, you can't say "My iPhone 6 never…" because it was a different hardware platform, a different version of iOS, used different cellular radios that didn't support power hungry 5G and used LCD vs. OLED display technologies, among other things.
If someone finds a particular app uses 75% of their battery, that app's authors need to address that.