Transfer plan from Photoshop to Lightroom?

Contact the Portfolio team directly about transferring your Portfolio site from one account ID to another.  But if you maintain the same ID, you should not need to do anything.

https://help.myportfolio.com/hc/en-us/requests/new?ticket_form_id=177168

What you want is the deeply discounted Creative Cloud Photography Plan  -- approx $10/month for 12 months. Includes the very latest versions of:
-- Photoshop CC and Photoshop on iPad
-- Lightroom on desktop, mobile and the web
-- Lightroom Classic
-- Portfolio website + hosting
-- Spark with premium features
-- Bridge
-- 20 GB cloud storage (upgradable to 1 TB).
https://www.adobe.com/creativecloud/photography.html

You will need to cancel one plan before you can start another.  And early termination fees may apply unless you can persuade the agent to waive them.

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How do I Cancel my Subscription?
https://helpx.adobe.com/manage-account/using/cancel-subscription.html
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Subscription & Cancellation Terms:
https://www.adobe.com/legal/subscription-terms.html