Is this their plan?

Increase the number of Supreme Court justices??

The number of justices on the Supreme Court, like almost everything else about the judiciary, is not fixed by the Constitution but rather by simple statute. It could be increased from nine to 11, or 13, or more, and Democrats could fill those new seats with liberal appointees. It is long past time leading Democrats start wielding this idea as a threat of payback and radical escalation against the GOP. Not only might court packing be the only way to convince Republicans to compromise, but it is also an acceptable fallback position should the GOP insist on maintaining its ill-gotten grip on the federal court system for another decade.

https://theweek.com/articles/832609/pack-supreme-court