Windows 11 in itself isn't an issue because I'm running Dreamweaver with WA on it and it's fine, however I am using the latest versions of both Dreamweaver and WA extensions. Dreamweaver CS4 is around 15 years old and is no longer supported by Adobe or available in any form.
I don't think Adobe offers any option other than a monthly/annual subscription, so unfortunately if you want to continue using DW with WA, you will probably need to get a subscription, which means your software will always be up-to-date. Also, the WA extensions are now free to download so you can get the latest versions of those, although they will eventually reach end-of-life since there is no new development or update work being done since Ray's passing.