Changing file type associations/default file type handler

I need to have both Collabora and OnlyOffice installed in parallel, because Collabora is better at handling OpenDocument formats, while OnlyOffice does a better job with OpenXML.

However, for some reason, collabora always insists on being the default app for all documents, even though in the OnlyOffice settings I have checked that OnlyOffice should be the default handler for these file types. Does anyone know, where/how I can change this? Does nextcloud have something analogous to ~/.mailcap?