Hotspot works great, but how can I turn off hotspot so it won't come back when requested by another of my devices linked to it, short of disconnecting the six devices? Keeps using up my data time.

I travel full-time in my motorhome and periodically I am in places without wifi for extended periods. During these times I use the hotspot on my iPhone SE. It works great. I linked to two iPhones, iPad, dvr and android tv (to update channel guides), and firestick my system router. Other night shut off hotspot, shut off cellular access, and put phone to sleep. Next morning found hotspot back on and all my data allocation used. Seems TV requested internet for software update. Short of disconnecting access to all other devices, how can I assure hotspot is only activated when I manually turn it on?