Unfortunately, double-sided SSDs do not fit in the 2020 Dell XPS 13’s (models 9300 and 9310). The M.2 connector is not raised high enough from the motherboard, so there is not enough space for the SSD’s bottom chips.
As of writing this post, all 8TB and 4TB M.2 SSDs, as well as several 2TB models, are double-sided and therefore would not fit in the XPS 13. This includes the Sabrent Rocket series and the Corsair MP510, whose 2TB version is single-sided but 4TB version is double-sided: