You can try this way to override and modify utilities of Bootstrap in template:
1 -- Go to folder: /templates/t4_bs5_blank/local/scss/ if you not override yet, just created 2 files: template.scss and utilities.scss
2 -- In 'template.scss' file, load override for utilities
// Templates Variables.
@import "../../scss/vars";
// Local Variables.
@import "variables";
// Override bootstrap utilities
@import "utilities";
// Bootstrap styles.
@import "../../scss/bootstrap";
// Template styles.
@import "../../scss/all";
// Custom styles.
@import "custom";
In 'utilities.scss', define values for width as you wish.
$utilities: () !default;
$utilities: map-merge((
'width': (
property: width,
class: w,
values:(
0: 0%,
10: 10%,
15: 15%,
20: 20%,
25: 25%,
50: 50%,
100: 100%
)
)
), $utilities);
I attached 2 files here so you can see: