Graphisoft discontinued QTVR support in AC 13:
http://www.graphisoft.com/downloads/goodies/AC13/QTVR.html
You can create animations in 15, but cannot create QTVR panoramas or objects.
The 'substitute' is the BIMx format and viewer... but for AC 15 and 16, BIMx was an extra-cost license:
http://www.graphisoft.com/downloads/bimx/bimx15.html
BIMx is included as part of the AC 17 and newer licenses:
http://www.graphisoft.com/archicad/archicad_17/faq/
You can still generate QTVR using Artlantis Studio.
(I'm not sure how you upgraded from 10 to 15... there aren't any upgrade paths that don't go completely to the present... unless you bought someone else's license to AC 15?)
One of the forum moderators
AC 28 USA and earlier • macOS Sequoia 15.2, MacBook Pro M2 Max 12CPU/30GPU cores, 32GB