iPhone 7 stuck at apple logo loop

74% is not healthy and is to be expected in a 5½ year-old battery. Have the battery replaced and all will be well:

iPhone Battery & Power Repair

About genuine iPhone batteries

Repair Provider Verification

(Articles found by searching Apple's Knowledge Base.)

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Contact Apple Support ->  Get Support (apple.com)

Check also this Apple article: If you see No Service or Searching on your iPhone or iPad

If you see No Service or Searching on your iPhone or iPad - Apple Support

If you still don't have a 'service' after that, see -> iPhone 7 Repair Program for "No Service" Issues

iPhone 7 Repair Program for "No Service" Issues - Apple Support

kelvin ~ Does your iPhone 7 still have its original battery?

And, if your iPhone becomes unstuck, what's the Maximum Capacity % here?...

Settings > Battery > Battery Health

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Now that it's working, again, what's the Maximum Capacity % here?...

Settings > Battery > Battery Health

(Note: That's not about storage capacity.)

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iphone 7 shut down and is cycling to apple logo continuously