MacOS – Can’t run 60hz on external display with MacBook Pro 15 2019

Apple today released an update that addresses external display support in Macbook Pros. Give that a try.

It's most likely because you are doing two conversions of the video signal and at some point it's either being degraded and/or becoming out of sync.

The two conversions I am referring to is going from DisplayPort to HDMI then going from HDMI to DVI. In your original question, you never mention specifically what adapters you are using nor if they are active or passive.

Why an "active" adapter? Active adapters "recreates" the signal and passive just reorders the signals.

To solve this issue, you need to limit your adapter to just one conversion (no conversions at all is ideal - mini DisplayPort to DisplayPort) and do so with an active DisplayPort to DVI adapter.