Exercise to stabilize my timing when pulling "fast" quarter-notes in right hand

Question

I'm looking for some kind of exercise I can do to stabilize my timing and groove when playing "fast" quarter notes?

Background:

I'm a self-taught piano player. I also have some experience in playing the guitar. Right now I want to improve my bass guitar skills. (I have a little home studio where I want to record my own songs).

Problem:

On the bass guitar I am able to play some even more complex basslines. As long as there are some rests in the bassline, I can stay in time and make it groove. Even if the bassline contains some quarter notes, I can stay in time. But when I try to play just "fast" consistent quarter notes, I completely mess up the timing.

I use my second and third finger alternately to plug the string. I can play fast quarter notes on the piano and the guitar. I think the problem is my right-hand fingers not being accustomed to the motion of "fast" plugging the strings.

Here is an example of a bassline where I mess up:

The Song is "Dark Necessities" by the "Red Hot Chili Peppers"

Solution-approach:

To fix this problem, I am slowing down the tempo really hard until I can stay in time and slowly increase the tempo. Since I don't get to play the bass guitar too often, I wonder if there is some kind of exercise I can do (especially without the guitar) to support my progress.

Q: Is there some kind of exercise (with or especially without a bass guitar) I can do to stabilize my timing and groove when playing "fast" quarter notes?

Answer 1

Q: Is there some kind of exercise (with or especially without a bass-guitar) i can do to stabilize my timing and groove when playing "fast" quater-notes?

Slow methodical repetitious practicing with the metronome and bumping up the tempo over time until you can play continuously at the desired speed for extended periods of time. There is no trick, and no special exercise to develop stable speed. It is a long term process that changes you nerves and muscles.