I have a lot of Macs. If MS 365 even looks as though it will increase my costs, and it does, I will be waving bye-bye to MS products. Every single machine will be a Mac or will run Linux, probably Ubuntu or Mint, or BSD. All of them. Any machines which need office-type things (which will not include the servers) will run iWorks from Apple or LibreOffice.
We're well ahead of you there, we dropped the whole Microsoft circus years ago because we have very high security demands - losing Microsoft saved us a LOT of work.
I am not sure LO on iOS would be that much of a stretch, after all, there is such a thing as NeoOffice for macos (interesting because it fixes the one really irritating deficiency of LO, the inability to use the macos method to insert accented characters).
Could be an interesting project for next year's law students to sort out, must have a word with the Uni we work with :)