After upgrading from bootstrap 4.3.1 to 5.3.3 am getting error

I have upgraded bootstrap library from 4.3.1 to 5.3.3 and when I tried to run the code am getting error like this :

Uncaught Error: Module build failed (from ./node_modules/react-scripts/node_modules/sass-loader/dist/cjs.js):
SassError: calc(1.25rem * 1em) isn't a valid CSS value.
 @return if($return-calc == true, calc(#{$value1} + #{$value2}), $value1 + unquote(" + ") + $value2);

2. ./node_modules/react-scripts/node_modules/css-loader/dist/cjs.js??ref--5-oneOf-6-1!./node_modules/postcss-loader/src??postcss!./node_modules/resolve-url-loader??ref--5-oneOf-6-3!./node_modules/react-scripts/node_modules/sass-loader/dist/cjs.js??ref--5-oneOf-6-4!./src/styles/index.scss)
SassError: calc(1.25rem * 1em) isn't a valid CSS value.
 @return if($return-calc == true, calc(#{$value1} + #{$value2}), $value1 + unquote(" + ") + $value2);

The Sass error @return if($return-calc == true, calc(#{$value1} + #{$value2}), $value1 + unquote(" + ") + $value2); is in _variables.scss file

Can anyone help me to solve this issue?

I have upgraded the bootstrap library and along with that I have upgraded sass to 1.79.5 from 1.54.9, sass-loader, css-loader to latest versions and tried downgrading the versions also.

I tried reverting the bootstrap version to 4.3.1 and it is working fine problem is only when I upgrade it.

Can anyone help me to resolve this issue?