Why Python numpy is not respecting the provided delimiter

Question

New learner here. I'm trying to write a fixed-width file in Python. I did a lot of google search to find a module the can help achieve the goal. I'm attempting with numpy. The function is not respecting any of the provided delimiters.

Code

import pandas as pd
import numpy as np

data = {
  "Make": ['BMW', 'Toyota', 'Dodge', 'Honda'],
  "Model": ['X5', 'Camry', 'Caravan', 'Accord'],
  "Weight": [1020.25, 950.98, 1235.37, 940.9],
  "Year": [2021, 2023, 2019, 2014]
}

#load data into a DataFrame object:
df = pd.DataFrame(data)
print(df)

with open('test_output.txt', 'w') as outfile:
            fmt = '%-6s %-7s %-7s %-4s'
            np.savetxt(outfile, df.values,delimiter='*', fmt=fmt) #Testing with any delimiter

Code Output

Code output

Desired Output

Desired output

My desired output should not contain any spaces between the columns. I attempted delimiter='' and delimiter=' '. The function is not respecting any delimiter when I provide an fmt.

I'm open to use different modules.