A short update on my experience.
I lost the use of my phone apps after 13.3 in December 2019. The local Apple store only offered me the option to buy a new phone. 13.3 also caused my WiFi to take about 5 minutes to come back after a restart. It felt like a poor upgrade.
13.4 and 13.4.4 didn’t fix anything but also stopped video playback in all the common web browsers. Another poor upgrade.
I contacted Apple support five times, wrote to their head office, joined this thread and completed the online form to report a problem.
13.5, which I installed about two weeks ago, fixed the video playback in browser problem, the WiFi restart issue and for me things like my Canon Camera WiFi connection worked better. But it didn’t fix my phone apps which people on this forum said was related a known Audio ic chip problem caused by flexing of the iPhone 7 Plus. How this related to a software update is unclear.
An Apple representative contacted me out of the blue. She was very nice, as are all Apple people are, but after offering a €440 repair said she couldn’t help.
Someone here recommended someone on eBay in London who undertakes the Audio ic repair for £30 so last week I posted it to him from Northern Ireland (item 254567288764). A week later it was returned and my phone apps now work. This service is highly recommended.
Whilst I’m now happy this took six months to resolve and I can’t understand why Apple didn't take responsibility and offer this repair at a similar cost.
May I thank everyone here for their thoughts and suggestions.
Take care because I guess things like a global pandemic are more important.
Rob