Systems broken, it’s her only option. If she endorses a progressive challenger to Biden she is basically saying she wants trump or desantis to be the next president. I am sure she is aware of this

Vote in more progressive candidates to congress and the house so that actual electoral reform has a hope of passing. The small contingency they hold is pointless from a legislative standpoint but promising in terms of growth over the past decade and a half or so. The more bodies we get in there the more actual shit might happen; but unless we displace neolibs and conservatives these stupid games will continue to be necessary