npub1t3pjtms82njzz9l8fh22nsrjlkwpnunseyntv6umt63h8ckk572sgqxdwy (npub1t3p…xdwy) these two sites are crowdsourced indexes providing you lists of many alternative applications to whatever you name.
https://alternativeto.net/
https://www.opensourcealternative.to/
https://alternativeto.net/browse/search/?q=onenote
https://www.opensourcealternative.to/project/Joplin
https://www.opensourcealternative.to/project/Trilium-Notes
https://www.opensourcealternative.to/project/Xournalpp
https://www.opensourcealternative.to/project/Standardnotes
org mode tools like orgzly
https://alternativeto.net/software/org-mode/