In case anybody would like to go further, here are a few articles I've written on these topics.

https://www.stpeterinstitute.com/post/david-and-moses

https://www.stpeterinstitute.com/post/false-there-is-no-more-punishment-for-sins

https://www.stpeterinstitute.com/post/catholics-earn-their-way-into-heaven