Question about Acer Hotspot Connect M5

I disabled once the " Optimized battery charging: ", that time later seems to get re-enabled by default. And since then I don't have those shutdowns... But it happened rarely, like 3 or 4 times in a month or two.. I use the M5 moden/router as my main internet at home, so I would notice..

Yes, i.e. I don't know if it disconnects but I have to keep entering the SIM card PIN.