I can't speak to the intentions of the person operating the jammer - if a person were using a jammer believing it to be prophylactic of the effects of radiation

I can't speak to the intentions of the person operating the jammer - if a person were using a jammer believing it to be prophylactic of the effects of radiation by 5G radios it may not be useful to ask what frequencies they were trying to jam. Anyways, the excerpts from DDG results for the BG-E8 5G list its jamming spectrum as 870MHz to 5850MHz. And for probably 98+% of users that will cover the frequencies in use where they live. The "high band" frequencies (25-100GHz) have a much shorter range, very low penetrating power (essentially you need to have line of sight to the antenna), and really only make sense in very high density areas like stadiums and maybe urban cores.