Yeah I have the same two (but how did you swap ahead/behind with HR?) - my wish was that the second that I also have, had some kind og speed. Like yours mine shows the current and next work/recovery but not current speed.
My interval is defined in intervals.icu and then synced to the watch via the Watchletic app.
I suspect the difference is the "target"?
So mine was a 1km interval with a target pace of 5:00 (which gets converted to a range because of how I have intervals.icu configured)...so on my "second screen" I see "1,000m 4'55"-5'05" where to me it looks most likely that your 5minute "Training" is just configured as an OPEN 5 minutes, and so you see just "5.00" in the small text (with no small text giving a pace/HR/power/whatever target).
Try and redefine with a target of some type, and the bottom field on the 1st screen will likely change to what is relevant for that step.
As an aside...all my training is HR based usually, but I'm using Garmin PacePro to create an elevation based plan for an upcoming race, and intend then re-creating the PacePro plan as a structured workout with an interval defined for each split of the Garmin plan to help guide me (Loch Ness marathon, which has an odd profile that I need some guidance from my wrist on!).