iPhone 8 Plus operating videos and opening bank apps on it's own

Sounds like your Digitizer may be failing. It is built into the Screen and will recognize "ghost touches" that appear to take over your phone when it is failing. That is common if the screen is cracked, but can also happens when the screen appears fine. If it continues, then take it to Apple for diagnostics. A screen replacement will solve the problem of a failing digitizer. As always, any repair needs to be done by Apple or Authorized Apple Service Provider.

Mac Jim ID wrote:

Sounds like your Digitizer may be failing. It is built into the Screen and will recognize "ghost touches" that appear to take over your phone when it is failing. That is common if the screen is cracked, but can also happens when the screen appears fine. If it continues, then take it to Apple for diagnostics. A screen replacement will solve the problem of a failing digitizer. As always, any repair needs to be done by Apple or Authorized Apple Service Provider.

Great answer, Mac Jim ID. I think you hit the nail in the spot.

Your iPhone is unlikely to be hacked, but may be experiencing some ghost touches.

Go to Settings > Battery > Battery Health and Charging. What does the percent say?

Jklaakdj wrote:

I changed it at a local phone-service store.

Does it show up on this site when you enter your city, location, or zip code?

Find Locations - Apple

Jklaakdj wrote:

100% I had it changed in the fall.

Where did you have it changed? It's been a few months since the fall and I would assume your battery health should have dropped a percent or two by now.