I think the theme makes a difference with phpBB.

Ex. This paid phpBB  theme 

https://themeforest.net/item/milk-multipurpose-responsive-phpbb-31-theme/16119149?_gl=1*hyxh73*_ga*NDg2NzczNTI4LjE3MzIyMjgxMTU.*_ga_ZKBVC1X78F*MTczMjIzMDE2NS4xLjEuMTczMjIzMDczNy42MC4wLjA.&_ga=2.51971113.1205794474.1732228115-486773528.1732228115

is $30 but that's way less than around $200 for a XF license.  :shock: