can i publish a native app in the app store with own logo and name?
yes!
If the pro-membership is not paid or I terminate it what happens with the apps on the app and play store? (not the webapp)(native apps)
nothing
can i publish the apps as native?
Apps are published as AAB or IPA files
can i download the app as .ipa?
Unfortunately Apple do not currently permit this - we recommend using TestFlight though for the best testing experience on iOS
do the apps need internet connection to work?
If you use internet connected components they do; if you use offline components, they don’t
are there extra costs for publishing?
Different pricing tiers have publishing thresholds, PRO is designed specifically for individuals who have a project and want to publish it.
do i need an apple and android developer account?
This isn’t Thunkable-specific, but yes. Anyone who wants to publish their apps to either of the stores should maintain an account there. It’s just like running any other business, only it’s entirely digital!