Thanks - I have marked it as a question and as solved.

Kind Regards
Kaz

And thanks for sharing the details about how you proceeded.
Can you mark your topic as a question (using the "Topic Tools") and then mark it solved so it will be easier for other people to find it out ?

If you can't, ping me and I'll do it for you.

I hope you are all well and thank you again for your help and advice.

Just an updated:

This is what I did to get my phone close to what I need. 
The phone is taking updates from the stable channel.

Please note - this works for now but I cannot guarantee how long it will work but at the most, the crontab may need to be set up again with the two tasks.
I will need to monitor my contact and calendar exports in the Documents folder for the modified timestamps now and then.

I set up nextcloud account and installed ubsync on my phone. Marked my Documents folder as a backup dir (among others) in ubsync

I set up 4 scripts (.sh files) with execute permissions in Documents - this will also keep my scripts backed up - they will not have execute permissions if you need to pull them down from nextcloud:

#calendar_export.sh#!/bin/bash
export display=:0.0
export DBUS_SESSION_BUS_ADDRESS=$(ps -u phablet e | grep -Eo 'dbus-daemon.*address=unix:abstract=/tmp/dbus-[A-Za-z0-9]{10}' | tail -c35)
syncevolution --export /home/phablet/Documents/utcalendar.ical backend=evolution-calendar database=Personal

#calendar_import.sh
#!/bin/bash
syncevolution --delete-items backend=evolution-calendar --luids '*' export display=:0.0 && export dbus_session_bus_address=unix:abstract=/tmp/dbus-t5OB5i75dT && syncevolution --import /home/phablet/Documents/utcalendar.ical backend=evolution-calendar database=Personal

#contact_export.sh
#!/bin/bash
export display=:0.0
export DBUS_SESSION_BUS_ADDRESS=$(ps -u phablet e | grep -Eo 'dbus-daemon.*address=unix:abstract=/tmp/dbus-[A-Za-z0-9]{10}' | tail -c35)
syncevolution --export /home/phablet/Documents/utcontacts.vcf backend=evolution-contacts database=Personal

#contact_import.sh
#!/bin/bash
syncevolution --delete-items backend=evolution-contacts --luids '*'
export display=:0.0 && export dbus_session_bus_address=unix:abstract=/tmp/dbus-t5OB5i75dT && syncevolution --import /home/phablet/Documents/utcontacts.vcf backend=evolution-contacts database=Personal

To do the initial import I exported my contacts and calendar from gmail and renamed the files as utcontacts.vcf and utcalendar.ical and placed them in the Documents directory.
syncevolution needs a blank line after every END:VCARD and END:VCALENDAR in the contacts vcf and calendar ical files respectively.

I connected my phone to my laptop and did the following:

On the terminal:
adb shell
Note: After restarting the phone the drive will become read-only again from what I can tell (no promises) - I did not do these are root:
sudo mount -o remount,rw /
crontab -e

add the following - you can change the frequency to suit your needs:

30 2 * * * /home/phablet/Documents/contact_export.sh
31 2 * * * /home/phablet/Documents/calendar_export.sh

I am not sure how crontab works as every time you open it the filename is different but my scheduled tasks are present.

I have set up a tutanota email account so the only thing that I will not have on my UT phone is email notifications.

I think I have covered everything.

If you spot any problems or issues please let me know - thank you and good luck.

Kind Regards
Kaz

Thank you - I will try and get this set up in the next few days.

Kind Regards
Kaz

I will try the solution suggested by AppLee but I am hoping to find a solution which does the sync in the background without me worring about it.

I will post what I find here.

Thanks
Kaz

Thank you for your reply.

I will try with the solution you are using.
Are you using the ubsync app to sync your files?

I may have to go back to my android phone temporarily as the UT phone (nexus 5) started entering some digits on the emergency dialler by iteself while it was locked and on charge. I only realised due to the dialpad sounds - something strange going on there. Should I report this as a bug?

Thanks
Kaz

if you manage to make it work, please share the way to success.

What I would do (and what I did) is to use Nextcloud to sync your data.
The "Calendar" app is able to sync with Nextcloud and it works fine.

For contacts, in my experience you don't change them so often, so I make a manual backup using VCF format and I back it up using my nextcloud account.
To switch from google, you can simply export your contact list as VCF and import it to Nextcloud, it's fast and easy.

For email services, I use protonmail and disroot.
On UT I set my IMAP account in Dekko2 which works fine for me.