Using Odoo Studio, add some fields to the Product so you can flag which components you want to adjust the quantities for:

Here we can add the following three fields (the first is a Boolean, the next two are Float fields):

These have the following names in this example:

<group name="studio_group_biHP0" string="BoM Adjustments">
  <field name="x_studio_adjust_quantity_on_bom" string="Adjust Qty on BoM"/>
  <field name="x_studio_bom_extra_qty" string="Extra Quantity"/>
  <field name="x_studio_round_to_nearest" string="Round to Nearest"/>
</group>

Then you can create a Server Action like this (tested with v14, if you use v13 you would use Warning instead of UserError in the Extra Credit section):

for record in records:
  for component in record.move_raw_ids:
    if component.product_id.x_studio_adjust_quantity_on_bom:
      new_qty = component.product_uom_qty + component.product_id.x_studio_bom_extra_qty
      component['product_uom_qty'] = new_qty + 1 - (new_qty + 1) %  -component.product_id.x_studio_round_to_nearest

Be sure to click so that your Server Action shows up in the Action Menu on each single Manufacturing Order (and on the list of Manufacturing Orders).

You then get the following:
Extra Qty = 1; Round = 5 - an initial MO component quantity of 1,2,3 or 4 becomes 5
Extra Qty = 1; Round = 5 - an initial MO component quantity of 5,6,7,8 or 9 becomes 10
Extra Qty = 1; Round = 5 - an initial MO component quantity of 10,11,12,13,14 becomes 15

For reference:

https://realpython.com/python-modulo-operator/

Extra Credit:

You can create a field on the MO itself (a Boolean) to indicate if the BoM has already been bumped and check for this in the Server Action, so that if the MO has already been adjusted, the User sees a notification and quantities are not adjusted further.

First within the for record in records: loop (so on line 17, after checking and adjusting each component, at the same indent as the for on line 13):

record['x_bumped'] = True

Then prior to the for component in record.move_raw_ids: loop (so a new line 13 with all lines pushed down, at the same indent as the original line 13):

if record.x_bumped:
 raise UserError("This Manufacturing Order has already been bumped!")