I came here to say that measuring 26 (or any other number) every night sounds like a bug and should not happen, so probably should reach out to Suunto about that or try some other tool/watch to test it.
On the discussion part, I think it is common knowledge by now, that only reliable HRV measurement is in the morning and slightly worse but still reliable is overnight. And does not matter which number it is or what units it is used as (might be carrots per bucket), only trends matters.
I checked ads for eliteHRV app, so much nonsense haven’t seen for quite some time, a lot of “readiness score/stress level/prevent illness” type of things, that has 0 scientific proof.