Can't speak for the rest as I play with around 200ms ping. I do experience this weird inconsistency as well. There are times where my shots would land as I expect and my accuracy would be unreal (for this ping anyway). Then there are those times where every other enemy player (not just those with good strafing skills) seem to glide past my bullets and the blood splatters show up far behind my target.
It's all down to a combination of relative skill, play style, antilag implementation, frame rate, frame lag, input lag, and network lag.
The sentiment from scrim players is that ETL's antilag system is better than ETPro. Bullets land where they should and headshots are much easier to land. After playing on the Hirntot ETPro server, I have to agree with them.
Perhaps you can watch the shape of the lagometer graph to get a feel of the consistency of the network lag. A flat bar indicates a very stable ping and considered good: firstly, the game client can predict and render the enemy position more accurately; and secondly, hit sounds arrive at a consistent rate so you can micro-adjust your crosshair as you track the enemy's head.
Frame latency is an interesting issue. Recently, I noticed that just having Firefox running in the background makes the graphics jerkier and laggier, even though my FPS counter is stuck at 200. Even though we have powerful computers in 2022, we have everyday apps like web browsers that use GPU acceleration for graphics which can compete with the game for rendering resources. For reference, I have an AMD Ryzen 3800X (8-core) and an AMD RX6900XT card.
Play style is worth mentioning here. If you get into good positions and catch the enemy unaware from the side or from behind, your accuracy will improve dramatically as enemies are not strafing and firing back at you.
I hope you can continue to find enjoyment regardless and stay for a while