I'm really pleased to see that you're now able to see the table! Please forgive me here if I can't help you all the way as I'm straying into parts where I've not experienced this exact connector, but I'll do my best.
The error you're receiving is error 404 which is a commonly used error code for a server side issue. This is always not found, and therefore with the format of your GUID (which looks correct), it's complaining that it can't find the Worker with that GUID.
Now, before we try to solve that, I've noticed that you're manually triggering the flow and then getting all of the items before trying to find your record. This has added an 'Apply to Each', but we're trying to make sure that we send this email when a new worker is created which would be better than manually executing and searching all items. We have two options here:
1. Try to narrow down the items listed to one unique record based on a value you can actually get to, or,
2. Does this connector allow you to specify 'when a new record is created', where you can then select for it to trigger on the Worker table? If it does, this will allow you to take the correct GUID for the new Worker directly from the trigger for your Send Email step.
Again, apologies if this doesn't quite work, I'm counting on my theoretical knowledge of Connectors and practice experience with Dataverse in the hope that they match up!