Telephone on Saturday

Hello Rabbi. I have been debating the issue of electricity on Shabbat for a long time, and I have not been able to convince myself of the justification for prohibiting it. All the methods for prohibiting seem to me to be irrelevant at all. It is very clear that they see this as a rabbinical prohibition because we have not been able to find a reason to prohibit the comfort of some craftsman, so they say it is a rabbinical prohibition without explaining what makes it a prohibition that the Sages established to prohibit it (two thousand years ago?). The prohibition because of a child also seems somewhat narrow. Likewise, ovdin dhol also does not fall outside the category of the basket of prohibitions without reason that they want to prohibit at all costs. After all, it is no worse than a Sabbath clock. Only the prohibition due to custom is a little convincing, but since I do not have the halakha loose because I do not see a decent basis for the custom to prohibit it, but a custom without reason and based on a mistake (fear of speaking new things, perhaps?). I know that I have barged into an open door. And yet I would like to ask whether the rabbi was convinced for one of the reasons for the prohibition and why. And secondly, if I am not convinced, can I rely on my opinion of the halakha.