You should rename your variable to something else. id is already used for database records and incremented by default.
your_field = field.Integer(string="SST", default=lambda self: self.env['ir.sequence'].next_by_code('increment_your_field')
with :
<record id="increment_your_field_sequence" model="ir.sequence">
<field name="name">Field Incrementation</field>
<field name="code">increment_your_field</field>
<field name="prefix"></field>
<field name="padding">3</field>
<field name="company_id" eval="False"/>
</record>
Padding may be changed to a higher number, it's based on how records you may have ( in this case, you will get 001,002,003,004,005,006...999)
You can do this by sequence in odoo: https://learnopenerp.blogspot.com/2020/08/generate-create-sequence-number-odoo.html
have a look