This counteroffer is so weird. These ten "moderate" Republicans are betting that Biden will want a COVID relief package that is deemed to be "bipartisan" more than he wants his his version of the package, filled with extremely popular items that are left out of the Republican "compromise" plan. The average American does not give a shit whether something is labeled as "bipartisan". But they want higher COVID relief payments, more unemployment enhancement, more federal funding for vaccinations and local governments, and a minimum wage hike. Weeks or months from now, when the actual dollars start flowing, few will even remember how bipartisan the bill was. But they will notice whether Biden's stimulus check was better than Trump's stimulus check.
Seriously, Biden has no incentive at all to give the counteroffer the time of day. The only people who think otherwise are those weird Washington junkies, who think that the "bipartisan" label has any cache outside of the beltway.