It's completely possible, though I'm currently having difficulty doing so but that is on testnet so I'm not too sure about main net.
On your offline computer, go to Help>Console and key in this:
getaddressinfo YOURADDRESS
You should get an output with loads of info. And take note of that field.
![](https://ip.bitcointalk.org/?u=https%3A%2F%2Fi.imgur.com%2FRpeOI2q.png&t=665&c=lnIeop_g9SBgBA)
Generate another receiving address and transfer both the desc and that receiving address to the online Bitcoin Core.
Next, go to your online Bitcoin Core and key in this:
importmulti '[{"desc" : "wpkh(026641b79d7ffa40ddf994f0277c2649f3ddcbd871194ba6ef87687daea22ca503)#zl4yt8hu","timestamp" : 0,"label" : "watch-address-test", "watchonly": true}]'
after that,
Use the code below
walletcreatefundedpsbt '[]' '[{"DESTINATION ADDRESS":AMOUNT}]' '{"includeWatching":true,"changeAddress":"CHANGEADDRESS"}'
Afterwhich, you'll have a long string. Copy that and save it to a file and transfer it to the offline computer.
![](https://ip.bitcointalk.org/?u=https%3A%2F%2Fi.imgur.com%2FYtSbS5a.png&t=665&c=QaAWD-cyO-lJtw)
On the offline computer, go to the file and copy the string again. Then go to Bitcoin Core, File>Load PSBT from clipboard.
A dialog will show up with the information, double check that the change address specified is from your offline wallet, the destination is as intended as well as the amount. If everything checks out, press sign TX. Press Copy to clipboard and save it to a file for transfer to your online computer.
After moving it to your online computer, open the file and copy its contents to clipboard. On the online Bitcoin Core, go to File>Load PSBT from clipboard and check it one final time before pressing Broadcast TX.
Personally, I don't think Bitcoin Core is designed for airgapped storage as it doesn't offer master public keys to easily create a watch-only wallet or is the UI that optimized for such a thing as well.