Can iPhone case interfere with hotspot signal?

Until the only local internet provider constructs its new tower, I am dependent on my iPhone 12 mini’s hotspot And I get just one to two bars of cell reception. No landline phone service for miles. Needless to say, I cannot install any security updates to my MB Air or iMac. Those and my old iPad air and AppleTV (4th gen) plod along on my hotspot. This has been the situation for months due to supply-chain disruptions caused by Covid. Metal, wood, other materials hard to come by.

Anyway, this is Verizon country (remote Wyoming). I was wondering whence cometh the iPhone hotspot signal and how it is transmitted when not tethered directly to a Mac. Could its hard case and/or skinny magnet in the case (for dash mount) interfere? I don’t really want to go to trouble and expense of signal booster for (hopefully) short-term problem (she says after already enduring 3+ months of delays).

One other related question - is it possible to tether phone to ATV?

iPhone 13 mini arriving this week and I am hoping it may do better.