I've had the Astro for six weeks (in Australia on Telstra), and did not encounter any cellular connection issues until just recently (though admittedly, I haven't left the house a lot in that time other than to walk my dog locally).
Maybe two weeks ago, I noticed as I was getting in the car at home that the phone signal would not connect, which I needed for GPS. Luckily a quick reboot sorted it out.
But last weekend I went camping, and on my way home, stopped for dinner in the tiny town of Nar Nar Goon. The phone would repeatedly show strong 5G connection briefly then sit back at no connection. I switched to 4G mode, and it did the same thing for that. Rebooting did not help. I don't know what the signal is supposed to be like in that town, so can't be certain that this was an issue with the Astro in particular. But there was clearly strong phone signal displayed; and I was in the centre of town, so if anywhere would have signal it'd be there. And from the EE issue I've been hearing about and the incident earlier at home, I'm made to believe the Astro is very likely at fault.
The road trip situation was extremely inconvenient, as I needed to let someone know I was on my way; and also needed Google Maps to work! I was heavily dependent on the Astro in this situation, and this experience has made me seriously question its reliability.