You can of course use alternative calculations / weights, but without a principled way to do so, you can choose weights to come up with pretty much any outcome that you like.
Also worth mentioning that the QoL index considers "climate index" which is almost meaningless, and apparently doesn't account for factors like "suffers from tropical cyclones".
Comments
Numbeo already includes (among other factors) CoL in their QoL index calculation, see: qhttps://www.numbeo.com/quality-of-life/indices_explained.jsp
You can of course use alternative calculations / weights, but without a principled way to do so, you can choose weights to come up with pretty much any outcome that you like.
Also worth mentioning that the QoL index considers "climate index" which is almost meaningless, and apparently doesn't account for factors like "suffers from tropical cyclones".