On top of that, IIRC the student loan aid was executive action alone (i.e. Biden specifically enacted it) while the pandemic checks were passed by congress so at best Trump might be able to say he pushed for it but it was still congress that made it happen.
Senate seats are ALWAYS state-wide elections, with no district lines to draw or gerrymander. Gerrymandering still arguably has an impact on senate elections, but it’s a secondary factor of reducing turnout and not a primary factor of just picking the best districts.