There are still plenty of lead alloys available from other sources. (My primary sources will be a plumbing supply company {pure lead} and a metal recycler {other alloys}, in the very near future.)
But wheel weights are definitely harder to get.
As I've detailed before in this forum, I can't even find a tire shop that sells theirs (to anyone) any more. They're all locked into recycling contracts by their WW suppliers. The only WWs I've ever been able to get my hands on were a coffee can full from when my grandfather used to walk several miles a day, and picked them up on the road; and a few WWs from some wheels that were being scrapped.
All of my "Wheel Weight" ingots were alloyed from pure lead, linotype, and tin solder.