Using buttons for filtering posts on Post (FrontPage)

HI,

we have no issues, we need only some suggestions, how to implement the following requirement.

Actually we have a blog menu https://davidmihalka.com/en/blog-en based on Posts ( Front Page). With its menuitems it is possible to shows the posts of certain category, e.g:

https://davidmihalka.com/en/blog-en/thoughts
https://davidmihalka.com/en/blog-en/stories
...

Requirements:

1) The https://davidmihalka.com/en/blog-en still should shows all posts, without any filter
2) Additionally should be selected posts of certain category using buttons (or similar) on top of the page.

Issues:

a) If I could create a custom module based on Posts (FrontPage), then there will be a solution.... But is not possible.
b) I can not extend the generated page https://davidmihalka.com/en/blog-en with the settings, they are.
c) A solution with fixed / horizontal menuitems would most probably not possible: https://forum.joomla.org/viewtopic.php?f=706&;t=969833 (my ticket)

Have you any idea, how to implement it ?

Thanks,

Michel