Is it possible to make my battery percentage higher

After the recalibration of your battery health reporting system, that number should increase. - About recalibration of battery health reporting in iOS 14.5 - Apple Support

As you have an iPhone 11, then yes after the recalibration it may be somewhat higher.

I would use "may" instead of "should". A tip for you the OP actually came from the link that you posted and either didn't read it or it wasn't specific enough for them. You can refer them back to the link rather than posting it again.

Keep up the good work.