1P_Dave
You raise a good point with that caution. Some services like Gmail let you generate emergency passwords to use if you lose access to your TOTP token. If Fidelity offers that then there's some protection against the concern that you raise. If not then your point is very well taken!
To clarify, what's described at the link I gave isn't online conversion tools; it's packages that one downloads and then runs locally. I imagine that online conversion tools would raise similar security concerns to online password generators!
Thanks again.