The D5's low ISO dynamic range is obviously a trade-off for it's ability to maintain good dynamic range at very high ISOs. It's one of the very best on the market in that respect. Don't like it, don't buy it.
As far as the D7500 is concerned, don't take Dx0marks scores for gospel. The larger pixel pitch of the D7500 gives it much better dynamic range from ISO 400 onwards than the SAMSUNG.
Dx0mark's maths is massively biased towards high res sensors. And doesn't take into account DR at high ISOs. The sports score is also effectively meaningless as a result
What's the difference between a score of 1300 ISO and 1400 ISO. less than 1/6 of a stop??? how is that a useful metric? When the d7500 is a full stop ahead of the SAMSUNG in dynamic range at high ISOs. They've gotten their maths all muddled up in the color depth scoring (which is heaving biased to high res camers), which has a big effect on the sports score.
We're talking about difference here of 1/3 to 1/6 of a stop in DR, and about APSC sensor that are closing in on their theorital limits between trade-offs of SNR and pixel pitch. This is a pointless discussion. When all APSC nikons have been more than good enough since the D7000,