I wanted to point out that Dominican Republic has always had a large portion of F2B. I looked up past few years before Covid and these were their F2B totals:
2019: 8,195
2018: 10,741
2017: 7,734
2016: 6,832
2015: 8,243
So this isn't something new that popped up recently, so theoretically that means DR is not the sole reason for no movement. I wish USCIS published the amount of applicants with PD before the final action date for F2B. That data point would be helpful.