HELP NEEDED - changing default - terminal & removing app store

q1.

how do i change ubuntu’s default terminal to the flatpak version of Konsole

an then safely remove the original without breaking the os an or desktop ?

q2.

how can i remove or permintly disable gnome software center without breaking the os,gnome plug-in & extensions or desktop ?

fyi.

i already removed the ubuntu one to as either tends to always run in the background sucking ram when i dont need it to an either always install an app 50% of the time buggly

since my last two rigs were built i prefer updating & upgrade & installing all my app wither .deb , appimage , or flatpak vi terminal an have better less buggy time doing so.