Aren’t there federal laws involved in those states actions?
Yes but what they're saying is that what happens in Pennsylvania does not impact Texas voters. Texas claimed it did and the court obviously didn't agree.
“...Aren’t there federal laws involved in those states actions?...”
As of now, there is no longer a Constitution and ALL federal laws are basically null & void...ALL of em.
Forget federal law of a moment....Article II of the U.S. Constitution was violated when those state's Secretary of State made up new election laws...thereby bypassing and usurping their state legislatures.
Furthermore, the SCOTUS itself, in Foster v. Love, stated the we have an "election day" and that voting can NOT go on past the federal "election day."
SCOTUS 9-0: Election Day Is One Single Day. Listen to oral argument from Foster v. Love (1997)
Those states that continued to count votes on 00:00 of Nov 4th onward, violated SCOTUS "precedent"....a unanimous decision no less.