Impedance matching on DC voltage line to remove ringing/reflections
At 20&nbsp;ns/division, edge rates of 2&nbsp;ns, you need to dampen; use 50&nbsp;ohms and 33/47/68/100 pF in series from trace/wire to GND. Or try 100&nbsp;ohms and a small capacitor.

By the way, your ringing frequency of 100&nbsp;MHz is where 15&nbsp;pF probes and 100&nbsp;nH scope-probe ground leads (6") resonate.

Bypass your ICs, right at the package. Using SMT capacitors. On ground planes.