As I pointed out in post #180, Remain in Mexico (otherwise known as the Migrant Protection Protocols) did not have a significant effect on illegal immigration. If anything, the program actually made the problem worse - tell people that you're going to ramp up enforcement, and they'll scramble to get into the country before the new program goes into effect. That's readily apparent if you look at the 2019 Border Patrol encounter numbers.
Yes, the problem did get worse after Biden ended the program, but it was already getting worse before he did that, and several significant events that affected the number of migrants worldwide occurred between 2019 and 2021. Given the lack of effect that the MPPs had on illegal immigration numbers (2019 surge aside), it's unreasonable to expect that they would have done anything to improve the current situation.