Is there a mobile provider that actually works?

It feels like a dumb question to ask, and maybe I am expecting too much - but I just want a service that 'works'...

Currently with EE (~4 years), and finding that numerous places struggle for signal - many being in large towns / cities such as Chichester / Brighton / Didcot / Croydon etc. In most cases - I'm not looking for streaming etc - just enough data to do a price check etc.

I have to rely on Wi-Fi calling as often have variable signal at home, and signal in the village where I live is non-existent.

Tried Smarty (Three) and whilst signal is better in some of those spots, we noticed the phone call quality was much poorer, so are not entirely sold with 3 / MVNOs.

've not touched O2 / Vodafone for decades - but understand their networks are lagging way behind in terms of 5G coverage, and in O2's case lack Wi-Fi calling - also know from friends/family who've used Vodafone and struggled with signal in smaller villages etc.

It's a situation that's certainly got worse over time - largely down to I suspect 'upgrading' the network to newer technologies but they don't have the same reach. I used to regularly hold conversations during commutes with my partner but that's now impossible without frustrations of signal loss - data certainly become more sketchy during that time, where even if you have a 4G reception you'll be lucky to actually load anything. This is across multiple 4G/5G iPhones too.

Perhaps more a rant - but short of trawling across networks with rolling contracts to get to something more reliable - or even needing to have dual SIMs to switch between the best signal are considerations I should not really need to take...