New Install of BC Core with old data in ubuntu

[merlinsilk]

Bitcoin Client Software and Version Number: 24.0.1
Operating System: ubuntu 22.04
System Hardware Specs: I5 8GB memory several HD with 6-7 TB
Description of Problem: unable to get BCCore running as a user
Any Related Addresses: no
Any Related Transaction IDs: no
Screenshot of the problem: none
Log Files from the Bitcoin Client: don't know where to find them

I had BC Core running on a 20.04 Ubuntu as user gezi for years. It had an external 5TB drive with a directory .bitcoin containing all data relating to this installation. The drive was mounted on /u/bigdata2.
The hardware failed and I replace the machine and used the opportunity to start fresh with ubuntu 22.04. The 5TB drive was again mounted on /u/bigdata2.
I installed the latest BC Core as a snap.
On first start BC Core asked me for choose the data directory, but I could not select /u/bigdata2/.bitcoin - the file selector did not show the /u folder at all. When I tried to type in the full datapath the Choose button remained grayed.
I tried everything I could imagine to get this to work, including adding dataDir=/u/bigdata2/.bitcoin to the config file Bitcoin-QT.conf in
/home/gezi/snap/bitcoin-core/bitcoin-core/126/.config/Bitcoin
In order get something to work avoiding any file permission I tried to run as root:
/snap/bitcoin-core/126/bin/bitcoin-qt -datadir=/u/bigdata2/.bitcoin
and that actually worked: it got the right data, it was a few days behind but it started the synching nicely.

Obviously I tried the same command as user gezi, but first got  popup window with a Payment request error, and then
"Error: Error initializing wallet database environment "/u/bigdata2/.bitcoin"! This error could occur if this wallet was not shutdown cleanly and was last loaded using a build with a newer version of Berkeley DB. If so, please use the software that last loaded this wallet"

The last I tried was to accept the default data location and started to sync. Then, when it thought be only 5 days until done, I did as user gezi
cd ~/snap/bitcoin-core/common
mv .bitcoin save.bitcoin
ln -s /u/bigdata2/.bitcoin .bitcoin
to plant the old data into the new nest, but to no avail: BC Core thought it was a new install and asked me for the data directory again.

I am now at  total loss and hope somebody can make sense if this all.
Thanks, Merlin

[nc50lc]

Bitcoin Client Software and Version Number: 24.0.1
-snip-
Obviously I tried the same command as user gezi, but first got  popup window with a Payment request error, and then
"Error: Error initializing wallet database environment "/u/bigdata2/.bitcoin"! This error could occur if this wallet was not shutdown cleanly and was last loaded using a build with a newer version of Berkeley DB. If so, please use the software that last loaded this wallet"

Retry this but with the same version of Bitcoin Core that you've used with that data directory.
If you forgot which version was it, go to the datadir and open your "debug.log" file and look for lines with "Bitcoin Core version vN.N.N" with the appropriate timestamp.

[merlinsilk]

I took Alexander the Great as an example (with his Gordic knot) and get rid of the snap and installed from the normal ...tar.gz like a proper application.

[merlinsilk]

Wow thanks - I did not know that snap was at least partially proprietary!
Speaking of snap - I am still lacking basic understanding of the inner workings and principles;
could you give me a hint where I can find out why (and how to fix) I am not seeing my directory
/u at all in two snap applications that I tried - bitcoin and Krita?
This is a directory that is fully accessible by everybody and I am using that for mounting all
of my external resources, so I need my apps to be able to see that.
Cheers,
Merlin