The Conservative Party no longer have a majority in the House of Commons. Therefore, it is pointless proroguing parliament to outline their legislative agenda as none of it will pass.
The Conservative Party no longer command a majority in the House of Commons. The prorogation to allow them to outline their legislative agenda was, therefore, pointless. None of their agenda will pass and become law.
In order to pass laws in the House of Commons, the bill needs the support of the majority of MPs. Johnson no longer controls a majority of MPs. Therefore, he will find it almost impossible to carry out any of his legislative agenda. Proroguing parliament to put together a Queen's speech and outline the legislative agenda, is essentially calling a halt to proceedings to put together a wishlist of items that will never come to fruition. It is utterly pointless.
Just because the Conservative Party doesn’t hold a majority doesn’t mean ending the session to outline a new legislative agenda was pointless. The parliamentary session had been the longest since the Civil War and it needed to be brought to an end. If the prorogation served no other function other than that, it would still have been worthwhile.  Johnson’s legislative agenda also includes bills to invest in the NHS, tackle violent crime and slash the cost of living, all of which could attract cross-party support and pass into law. Putting these items on the legislative agenda to bring before the House of Commons was not pointless and could be of significance in the coming months.  Also, just because it was pointless doesn't mean it didn't need to be done. If the governing bodies never did anything that was pointless, the whole September session would have been prorogued. Its legislative function was virtually nil and it was a mere show for MPs to be seen making a lot of noise to justify their exorbitant salaries.
[P1] Bills need the support of the majority of MPs to become law. [P2] Boris Johnson does not command a majority of MPs. [P3] Therefore, it will be almost impossible to realise his legislative agenda. [P4] Therefore, any pause to outline his legislative agenda is pointless.
[Rejecting P3] There is no reason why many of the legislative items shouldn't garner cross-party support in the commons. [Rejecting P4] The prorogation was not pointless. It was necessary to end the previous parliamentary session.