Does cds deploy and cds build work w/o being in the folder?
Or would it make sense to include a cd shared-db step and not mention the folder with every command?

Good point, for the context of the 'Try it out' box a cd shared-db step could make sense.
cds build shared-db --for hana works, but cds deploy only works in the folder.

Changing directories can be confusing, a subsequent cd .. is also required, in addition the suggested change shows that the cds command in that case consumes a model and the db parameter is not a command but a directory with a cds model. Afterwards the guide continues in the root directory so better make sure we stay there.

In line 165 what does cds deploy deploy? This would then also need the "shared-db" as part of the command, or?

Same question for line 168.

We can use the cds compile command to make it more clear what happens,. It seems to be the default command, thus skipped.

cds compile shared-db/db --to hana
cds compile shared-db/db --to sql

In line 165 what does cds deploy deploy? This would then also need the "shared-db" as part of the command, or?

Same question for line 168.

You are right, we need the models here also:

npx cds deploy -2 sqlite
No .cds models found, please specify one as an argument

just uploaded the "cd shared-db" variant for the whole block - commands work now