Help with Valvesprings and valve float. Noob

Let me guess...... Chinese rocker gear?
The shafts may be hardened...... but they don’t appear to be hard enough.

The shims under the springs look like they are the low performance, non-heat treated variety.
When used with aggressive cams and springs that are likely not happy at rpm......that’s what they’ll look like.
The heat treated ones hold up better, but can still get chewed up over time.

A spring seat is needed to eliminate that issue.
Some machining on the heads may be required.

Looking closer at the pics of your rockers and retainers, it appears as though you took it apart before some impending doom.
The highest point of the retainer appears(looks like there are witness marks on both the rocker and retainer...... but I’m just looking at pics on my phone) to have some contact with the area under the rocker by the spring relief cut.
This usually results in the retainer/keepers/valve not staying “locked” together, allowing the them to work/move on the groove in the valve........ until it fails....... and it drops a valve.