I think if you do not mind that your WO id is the same as that of displayed, you can set .pyWorkIDPrefix to whatever you want using data-transform (except that the sequence number comes last). There are a lot of examples OOTB, just search .pyWorkIDPrefix in the developer portal.
If you need to change only how the label of the work object is displayed, you could try setting the label with the pega.u.d.setLabel script in the UserWorkForm HTML Fragment, mapped to your ruleset. This will be a custom implementation as opposed to the OOTB way of using "pyWorkIDPrefix" and "pyWorkIDSuffix" though, so heads up!
If the application ruleset is ABCOrg, Open the UserWorkForm HTML Fragment specific to that ruleset and implement your logic. A sample implementation has been given below.