There are only two suitable mediums: E-Mail or phone call.
99% of incoming calls to my phone are spam. I won't pick up an unknown number unless someone has already contacted me and told me to be expecting a phone call, or it's a call from someone I already know (people I already know don't call me either).
That is to say, your mileage may vary on what counts as a "suitable medium".
If it indeed is something that you feel might be fishy, I further recommend the following: write a summary of what was discussed and send your summary to the people on the call as "meeting minutes -- 2026-02-11" (make this a habit, and always say "I do this routinely to remember what was agreed"). This can easily avoid you being trapped by dubious propsals or being unwittingly on the wrong side of the law.
Are there legal or other situations in which meeting minutes would be admissible in evidence, but a recording would not be? Obviously this is jurisdiction dependent.
Who except you would know that you have any recordings? They are just used to help you remember. Remembering exactly what was said.
You might have had your reasoning warped by lawyerings in this case.
if you make a recording, transcribe it, the delete the recording, it's probably hard to prove you made a recording. better yet with todays technology you can probably make a transcription live. i don't know if feeding he audio into a transcription tool counts as recording.
but the example was to use a recording in court. if you do that then everyone knows.