I can not comment on the condition of the wheel from where I am sat.
However, the usual reason for pressure loss from the bead is corroded or dirty faces.
If you take the wheel off and lie it flat and apply a mixture of water and fairy liquid all the way around the bead, you will soon see where it is leaking.
Tyre does not require to come all the way off to apply the sealer, all you have to do is break the bead.
However, to clean up properly the tyre is best removed.
Your tyre people will know how to fix a leaking tyre and they will also have the sealer that they will use on a daily basis.