Most GOP pundits have already conceded the Senate SCOTUS and prez will go Dem. They are best to spend their time and effort on the House
I haven't seen anything really on them conceding the Senate. That would be a strategic blunder. They have much more of a chance to block a Democratic Senate majority than winning the presidency, and the House is already favored to remain in GOP hands until the next round of redistricting. If a wave forms that could easily sweep that majority away, then their investments likely wouldn't help much anyway.