Worked Superbowl 2018, Imagine Fest 2023, and dozens of other high profile and low profile events with Imagine Fest being in the middle of nowhere as a COM-T/COM-L. Never had an issue with AT&T or T-Mobile, Verizon OTOH, had capacity issues at Imagine Fest. Planned events mean they bring in resources, so all that you are saying isn't reality in 2025. Carriers scale up for large events, and are building out and up their networks. It isn't 1999 and Woodstock 99 relying on AMPS and 2 carriers.
Ruggedized phones like Sonims are about what a good quality Anytone CCR costs and you can drown them, run over them and they don't die. Carriers often give them away to enterprise customers.
Cellular network expansion with small cells and picos is way cheaper, easier to deploy, and care free unlike LMR repeaters which are a massive pain in the ass, require coordination, not to mention qualified skilled technicians (not TEKNISHUNS) to setup and maintain. A device like a FirstNet small cell runs itself. Plug it in on your farm or shop, connect ethernet or sat, and walk away. No tech or truck roll needed. Sure, your repeater is yours, but it' just that: your problem. Unless you have a service monitor on hand, tons of cables, adapters, ISO-Ts, lots of experience and time on your hands when you're not plowing the fields to troubleshoot problems, seems like calling up AT&T, Verizon or T-Mo and getting an on-prem coverage enhancement solution is much cheaper and scalable, not to mention lower capital outlay than some complex self-maintained LMR system.