Remove unwanted padding/spacing in QTableWidget cells

I’ve created a QTableWidget and populated its last column with QPushButtons added inside a QButtonGroup (given in the code below):

from PyQt5.QtWidgets import *
from PyQt5.QtGui import *
from PyQt5.QtCore import *
import sys

class ModTableWidget(QTableWidget):
    def __init__(self):
        super().__init__(0, 3)
        self.setHorizontalHeaderLabels(["Alias", "Path", ""])
        
        self.horizontalHeader().setSectionResizeMode(0, QHeaderView.ResizeToContents)
        self.horizontalHeader().setSectionResizeMode(1, QHeaderView.Stretch)
        self.horizontalHeader().setSectionResizeMode(2, QHeaderView.ResizeToContents) 
        self.setSelectionBehavior(QAbstractItemView.SelectRows)

        self.is_default_group = QButtonGroup()

        for item in range(10):
            self.addItem(str(item), str(item))

    def addItem(self, alias, path):
        last_row_index = self.rowCount()
        self.insertRow(last_row_index)

        alias_item = QTableWidgetItem()
        alias_item.setText(alias)
        self.setItem(last_row_index, 0, alias_item)

        path_item = QTableWidgetItem()
        path_item.setText(path)
        self.setItem(last_row_index, 1, path_item)

        is_default_btn = QPushButton("Btn")
        is_default_btn.setMaximumWidth(30)
        is_default_btn.setCheckable(True)

        self.is_default_group.addButton(is_default_btn)
        self.setCellWidget(last_row_index, 2, is_default_btn)

if __name__ == '__main__':
    app = QApplication(sys.argv)

    tablewidget = ModTableWidget()
    tablewidget.show()

    sys.exit(app.exec_())

It is working fine, but it adds a little space on the last column:

I assume that it adds that little space by default, as it’s also noticeable on the images in this question. The most relevant question I found is this one, in which they talked about implementing custom painting through a delegate – though I’m not sure if this is the right path as I’m somewhat new to this concept.