My backup is on an earlier version of iOS. If I tried to restore a backup, will it downgrade my iOS version to the one that was on the backup?

My iPhone is stuck in this repeat loop where it constantly tries to restart my iPhone showing this Apple icon before it shuts down. So I'm going to try and preform a backup with iTunes on my PC I do have a backup stored but the backup has an older iOS version to the one I recently have installed now. Will this downgrade my iPhone 11 back to the iOS version stored on the backup or will it keep the iOS version I have installed? I'm not sure what iOS version is on the backup but before my iPhone got stuck in this repeat loop where like I said constantly tries to restart my phone was iOS 14. Will it downgrade my iOS or keep it?