To drive SRV sanely you need to disable drive assist. Though previously it worked.
I told you: this is another game which just pretends to be Elite we knew before Odyssey.
Drive assist, like it's flight equivalent Flight Assist, is a different 'model' that behaves in a different way. Most drive with DA-off as you imply, but if you are using a self-centring axis for SRV throttle drive assist will allow the player to 'bump up' (or down) the speed, like cruise control IRL. It's not objectively worse, it is just a different way to control the vehicle. Mouse users have a broadly similar toggle that FA-off kb/m users regularly have to switch over (absolute position vs relative).
The current issue with the excessive drift in some ships, particularly noticeable while docking appears to only happen with rotational correction on (the default). Switching it off to dock can give me a significant reduction in drift as a workaround, but unlike your drive assist example, it does appear to be a bug rather than intended behaviour.
Your opinion that the game is not what it was is acknowledged. Prior to the Odd launch the 'complete codebase rewrite' was often mooted to be the golden child. Time has told a different story.