How Can I Check The Battery Health? (With Or Without 3rd Party Apps)

The iphone has a battery health option under settings, battery, the ipad doesn’t seem to. You can at least see what’s using the battery.

as to third party apps I have no suggestion, you’d just have to search and read reviews to find one that looks good to you

The battery health feature is exclusive to iOS for iPhone. Inclusion of this feature is relatively recent.

iOS/iPadOS for iPad has never had the Battery Health feature - most likely because iPad batteries are both considerably larger and have a much longer service life. 

An iPad battery is rated to maintain at least 80% of its initial capacity after 1000 full charge/discharge cycles - whereas an iPhone is rated to have 80% of initial capacity after 500 full cycles.

There are software packages available that can access battery cycle count. Popular choices for Mac are Coconut Battery and iMazing - whereas iMazing is available for Windows PC.

https://www.coconut-flavour.com/coconutbattery/