after a search engine search, often i have not found what i want, partly because so much Windows results and partly because of complex requirements. of course i want software that runs fine on Ubuntu, even if i compile it from source.
what i want to ask is where is a appropriate forum or sub-forum to ask what software i can use, and ask for rating/opinions on what software is best (to the extent i have described my needs well enough).
Have you tried here?
Along the lines of what Rubi has already stated; I tend to explore using CLI or command line.
apt search which lets me search of packages by name or keyword (mostly what packages.ubuntu.com provides, but I can use some more complex POSIX type searches/filters)
snap search to search for snap packages which give more more choices than the deb choices that are found with prior apt command
flatpak search again searches for flatpak results; again more choices.
For appimage or compile from source I do tend to rely on online search results (google isn’t my preferred choice; but I’ll even try there as it is pretty good)
Stack Exchange (home of Ask Ubuntu) do provide https://softwarerecs.stackexchange.com/ but I’ve never used it (actually I’ve seen a few questions on Ask Ubuntu about software too; eg. here I answered)
For more advanced searches I use aptitude in TUI mode (like GUI but for Text interfaces). I have found lots of gems by searching something and following the (dependency) links to meta/virtual packages, for instance. One can even change the solver’s decision to choose a different dependency package, e.g. package A depends on B or C and the solver picks B but I want C.
Or, just use the Software Center search, which should span all official venues of distribution, be it snap or deb packages.