Is there an adaptor for a quick release wheel on thru axel hub

Usually, switching axle standards is accomplished by switching end caps on the hub. Whether this is possible or not entirely depends on what hub you have. You will need to do some research on whether your new hubs have convertible end caps.

I believe there’s generic adaptors available to shim down a 12mm thru-axle down to a 5mm QR skewer, but that’s the opposite use case from your intention.

Expanding a bit on @MaplePanda's answer: some wheels use hubs from major known brands like DT Swiss or White Industries. Some wheel manufacturers, especially premium ones like Zipp or Enve, may make (actually, I suspect they supply specifications to someone else, likely a factory in Taiwan or mainland China) their own hubs. Or some wheel manufacturers might have hubs with their own branding, but they actually come from an OEM manufacturer like Bitex, Novatec, Joytech, and a bunch of others I'm probably forgetting.

If you know who made the hubs, you can likely get the thru axle endcaps from that manufacturer's website or one of their dealers, especially if they're premium hubs. If you don't know who made the hubs, you need to go to the wheel manufacturer.

I think that the Axis 4.0 wheelset is a Specialized wheelset. For others' reference, Specialized is a bicycle manufacturer that's horizontally integrated. If that is indeed a Specialized wheelset, you would approach any Specialized dealer to ask.

Specialized has a premium wheel division called Roval. I don't think that the Axis wheels are made by Roval, and they certainly don't seem to be branded as Rovals. I have a suspicion (NB: I don't work in the bike industry, this is somewhat informed speculation) that the lower-end Axis wheels may use off the shelf parts, e.g. hubs by one of the Taiwanese manufacturers I mentioned earlier, probably rims by a Taiwan-based company as well (e.g. Alex wheels, Kinlin). Because the Axis wheels are relatively low end and are probably just specced as OEM equipment on Specialized bikes, it's possible that Specialized may not stock replacement endcaps for them. Or it's possible that the Specialized does but the store personnel have no idea how to find them, because replacing endcaps on a lower level OEM wheelset is probably not a frequent request. In this case, if you knew which OEM hub maker made the hubs, it might be possible to source the endcaps. The problem is, it's not necessarily easy for a consumer to tell which maker did this. On the off chance that you find a Novatec logo somewhere, you could try Bdopcycling.com. If you see a Bitex logo, you could try Bikehubstore.com. If you have a knowledgeable local wheelbuilder, they might even have an account with one of the OEM hub makers, which do produce inexpensive but pretty reliable hubs. The problem is that you would probably need to identify the hub by visual match to the manufacturer's catalog; I have had Novatec and Bitex hubs before but those companies' logos aren't anywhere on the hubs. That's precisely because they mainly sell as OEM equipment to companies or even individuals looking to make wheels. Indeed, my Bitex front hub is branded Speedcific, which was a single-person shop (unfortunately defunct).

The TL;DR of this somewhat meandering answer is that unless you know which company to approach for the correct endcaps, it's best to get a wheelset that has the correct endcaps to begin with. Again, I would try a Specialized dealer, and there are quite a number of them as Specialized is a major brand. I have a hunch that you should first try a store that exclusively sells Specialized bikes first, rather than a store that sells several models of bike that include Specialized. The exclusive dealers (I'm not sure what the correct term is) might be more familiar with Specialized's internal inventory systems.