This study is by people who know this error exists. The 5x number is based on a group of people that began with 4.7x as many incidents of POTS. The ratio being touted is the comparison of absolute numbers between two groups that started with a massive difference. The actual ratio difference is 15% ...1.3 vs 1.5.
I think the level of knowledge in the study can only conclude this was intentionally misleading as one graph intentionally leaves out the initial POTS numbers and ratio between start and end of the study.

Further, all they are actually demonstrating is that a group with 1 spike/furin exposure has less POTS than a group with 4 or more exposures