As far as I know, 7-Mode is scheduled to exit Limited Support on 12/31/2022, so it still has some time left. However, which certification makes sense for you highly depends on your personal situation. I don't work with 7-Mode myself on any of my systems, so it wouldn't make sense for me to pursue any 7-Mode certifications, but your mileage may vary depending on what type of systems you administer.
That being said, if it was me, I would focus on the certifications that are geared towards the ONTAP releases where the innovation is happening (so, not 7-Mode).
Hope that helps.
