Touch wood mines been fine @Gordie
Are you sure it's not your sim card that's been glitching ?
In regards to battery life and extending it this is a subjective topic as we all set up and use our phone's differently, use different apps, and have different signal strengths.
If you perform a forum search you'll see lots of ways to help with battery saving and useful tweaks.
One thing I'm not in favour of is turning Off useful features that I want or may use to save some juice.
Here are some things I do on my Fold.
- Dark Mode.
- Screen Time Out is 2 minutes.
- I only let my main email account sync regularly.
- I look at my app notifications and limit them if necessary.
- I've uninstalled the Facebook app and now access my Facebook via my internet url.
- I've disabled Google Chrome and only use Samsung Internet. In my experience Google Chrome is a resource hog.
- I only use the Samsung default theme.
- I don't use 3rd party launchers such as Nova Prime.
- I dont have nearby device scanning on as I dont need this.
- If I'm finished with an app that I know can use more battery in the background then I'll close it down. That said the phones nowadays are clever enough to eventually do this themselves.
- I dont use two sim cards on my phone as this can use more battery as the phone is working go keep connection to two networks, or I simply disable one sim until I need to se it.
- Location _ Improve accuracy is turned off.
- Adaptive Brightness is off and is set to around 50%
- Dark Wallpaper.
- I move apps I dont need notifications all the time from and that always need to work in the background to sleep mode.
- I move apps I dont need notifications from and work in the background to deep sleep mode.
- I dont use apk files.
- I don't use battery monitoring apps as they by there very nature constantly work in the background so use more battery.
- I run my phone on a full cycle and then check in my device care, battery section to see if an app is using more battery than I'm happy with.
- Once a week I use the optimisation feature,
- If my phone is misbehaving then I'll clear the phones system files. Clear your System File Cache via the instructions in the Samsung Link. You may need to hook upto a computer or insert your headphones to get to the recovery menu. https://www.samsung.com/uk/support/mobile-devices/how-do-i-clear-the-cache-on-my-device/
- I opt not to use the power saving mode as I want my phone working go it's optimum.
The best battery saving tip I learned years ago was to turn off the battery % sign in the top status bar so I'm not always drawn to looking at it and just enjoy what the phone brings. 
If necessary carry a handy portable power bank.
I wish you all the best with this situation.
