As noted the main issue with Thunderbird is its inability to reliably update counts in additional Imap folders other than the Inbox. One way around this is to have, as I do now, three general purpose email accounts which are graded as low, medium and high priority.
Having written about both last time I am getting more into depth this time around taking a serious look at what I can do with both pieces of software.
Since Evolution has turned out to have superior performance to Thunderbird I have decided to use Evolution for my day to day stuff and use Thunderbird for the accounts I am closing down until they close, it looks like Evolution can handle Gmail and Google Calendars and Contacts quite well without problems and Thunderbird has a lot of issues with not updating the counts in additional folders very well so I am working to implement this decision.
digiKam is an interesting piece of software that I need to evaluate further as well, one of the key considerations is whether it could take over from using a Windows computer to download and rename the photos from cameras. At the moment the key issue is whether I can get it to connect to any of my cameras. Initially Debian did not recognise a camera out of the box and it seemed the issue would be that the necessary capabilities are not by default enabled in Debian. When I tried plugging it into the mediapc running Xubuntu 17.10 it was detected and mounted immediately. After looking at some stuff with Debian I installed a package called pmount, and then plugged the camera back into the mainpc, and it was detected and mounted automatically as a USB mass storage device. digiKam has been able to import pictures from the camera and I am now testing it further to see how useful it might be and what I can do with it.