re: How do you get appropriations bills that Democrats will support?

You have to craft something that is palatable to both parties where both parties can claim a win. If you are good you get more than you want and you get them to take less.

If they Republicans really wanted to expose the Democrats they would offer an appropriations bill with tax credits that can be applied against tax liability or student loans, or partially refundable, and pay for those credits by eliminating SALT, the mortgage home interest deduction and the EITC, and other currently available continuing education tax credits. You can craft it in a way that it is revenue neutral and deficit decreasing.

That would put the Democrats in a position of either voting against student loan relief or agreeing to spending cuts.