You upgraded your Padshop Pro licence to Padshop 2. When you upgrade a Steinberg licence, the original licence is replaced with the upgraded licence, so your Padshop Pro licence was replaced by a Padshop 2 licence. There is no Pro and non-Pro distinction for Padshop 2 - all Padshop 2 users have access to the old Pro functionality and more. Similarly, when I upgraded Dorico 2 Pro to Dorico 3 Pro I no longer had a Dorico 2 Pro licence and when I upgraded Cubase 10 Pro to Cubase 10.5 Pro I no longer had a Cubase 10 Pro licence.
Those who upgrade a Cubase Pro or Artist licence to Cubase 10.5 can run Padshop 2 using their Cubase licence. In this scenario, any separate Padshop Pro licence is left untouched unless it is upgraded separately. Similarly, those who own Absolute 4 can run Padshop 2 using their Absolute licence, though they might have to run Maintenance on their eLicenser before it works.
In most cases, an upgraded licence will run older versions of the product. There are a few exceptions - IIRC a HALion 5 licence will not enable HALion 4. In these cases you can usually get a free additional licence for the legacy version from Steinberg Support that cannot be used to qualify an upgrade.
If you own Cubase 10 Pro or Artist, I would have upgraded that licence to Cubase 10.5 rather than a Padshop Pro licence to Padshop 2. You can run Cubase 10 using a 10.5 licence if you would rather stick with 10 for now. I know the Cubase licence upgrade is more money, but the chances are that you will eventually upgrade Cubase to a future version even if you skip 10.5 completely, so it seems to make more sense to put the money towards upgrading the licence for the larger product. A Cubase 10.5 Artist or Pro licences not just Cubase but also Retrologue 2, Padshop 2, Groove Agent 5 SE and a content bundle for HALion Sonic SE 3. All of these additional products other than Groove Agent 5 SE can be used in other DAWs, though you will have to install the standalone version of HALion Sonic SE if you haven’t done so already.