The bill was legitimately bipartisan, written by both Republicans and Democrats, and sponsored by both in the Senate. As for normal procedure, at least according to you, the House would have come up with their own version rather than declaring it "dead on arrival." And, again, it wasn't "dead on arrival" before Trump told them not to pass it.
As for not being needed, the reason I brought it up is because of the complaint of the backlog of immigration cases, of how long it takes for them to get "due process." The changes that border bill made were needed then and are still needed now, as it did a lot to improve and expedite the processing of illegal aliens.
As for border encounters, if they are down (unless people are getting across the border unseen) then it would seem it has something to do with less people trying to cross the border and largely unrelated to what a president has done. Biden didn't really change much in terms of Trump's previous rules, so it wasn't any type of "open borders" policies that caused people to flood across the border. So what changed? About all I can think of is all the Republicans who were on the news yelling about how we had "open borders" -- it wasn't true, again the policies had not been changed, yet something made thousands/millions decide to test the border. Democrats weren't talking about any type of "open border" and were capturing people crossing the border at record rates, as well as doing far more deportations that Trump has. So it makes no sense that so many would be trying to cross into the US illegally, other than the fact one political party, not the Democrats, was basically saying they could all come in and lying that Biden would let them in.