How can I factory/hard reset/wipe a Nokia 2.2 (TA-1188) without a (windows) PC?
Having now been in contact with Nokia support; Apparently there is no way, at least with that specific phone in question (or the specific firmware ver.?), to get it unlocked/factory reset, for the common user.

Fortunately, the dude at Nokia support chat checked the IMEI's of it, and it turned out it was still within warranty, by a hair's length. So having contacted the chain that sold it, a second time, it seems the local store will be replacing the phone tomorrow.

As such, and though depending on varying consumer rights in countries; My hindsight tip would be to first press the seller with the fact, rather than immediately "making an appointment" trough Nokia's online warranty form, to send the phone away to Nokia as was suggested by Nokia support; Simply for Nokia to do the "magic" of unlocking your bought and paid for property(!!), and sending it back to you ..Something which no doubt would have added considerably more time than the store simply replacing the device and having to deal with manufacturer warranty themselves.

BTW: If you are indeed able to get to the 'downed droid' splash logo on your Nokia 2.2 (TA-1188) trough any physical button-combo, you just might want to confirm with Nokia support whether your phone might be a counterfeit one or not, or to verity that it's not been flashed with unoriginal and thus possibly tampered-with firmware.. (just push your way trough their silly chat-bot for a few questions, and then an actual human will respond to your inquiry on the other end)

PS: Google did eventually come trough with assistance in recovering my brother's hacked/locked Google account. (takes ~3.5 days).. But seemingly, that process also unlinks it from the/any associated device(s). Which is good, from a security perspective.. ..Though the problem becomes then, that that effectively makes it impossible to reset from online Android Device Manager as shown trough some online how-to's .. Meaning, the phone would've basically be considered as good as destroyed, if it had not been for it still being within warranty timerange... (personally, I'll be looking at Librem phone for myself in the near future, rather than risk experience a similar ordeal and frustration)