Is anyone else getting the sense that their phone and data signal is declining in the Bristol area?

I've been with Vodafone for about 6 years and it's always been reliable. In the past 2-3 months I've found it not working at all for calls or data in various parts of the city, eg St Werburghs (which was always a bit dodgy but not totally useless) and in City Business Park near Trinity Centre where we have a kitchen. These are the places I notice the most, but not the only ones where it happens.

5G has been pretty useless ever since I got a 5G capable phone, so I tend to leave it off. Nowadays my phone will show 3 out of 4 bars for either 4G or 5G, but WhatsApp won't send and web pages won't load. Sometimes going in and out of aeroplane mode helps.

Is this just Vodafone? Any ideas why service has declined rather than improved? Is there some other setting I should be trying.