Here's a breakdown that could add some clarity to this topic. Since it highlights each QB vs other QBs of their "era" it should, at the very least, de-emphisize era rating bias.
Top 10 rated QB seasons
Romo = All 8 seasons played = 100%
2006 - 5
2007 - 5
2008 - 8
2009 - 8
2010 - Injured
2011 - 7
2012 - 10
2013 - 8
2014 - 1
2015 - Injured
Dak = 3 of his 6 seasons = 50%
2016 - 3
2017 - 16
2018 - 14
2019 - 10
2020 - Injured
2021 - 7
2022 - 16
Top 5 rated QB seasons
Romo = 3 of 8 = 38% - 2006, 2007, 2014
Dak = 1 of 6 = 17% - 2016
Average QB rating per season
Romo average 6.5
Dak = 11
Dak ranks 11th in his era while Romo ranked 6th or 7th in his era.
*Data excludes major Injury seasons for both and Romo "holder only" years.