CO2 carts have been the only way I’ve seated them so far. Two track pumps and neither have done it. Though I understand some are higher volume than others.
If you use CO2, just use it to seat the rim. Deflate and add sealant after as the two don’t mix. Pump back up with air.
If you’re stuck with the valves, you could ghetto some from old tubes. Just cut the valves from old tubes leaving a small amount of rubber at the base. Then need an o-ring for the other side, or you can make one from more of the old tube. Needs sealant to keep it from leaking.
Use sealant. Lots of sealant. I use at least 3 cups full of Stans. Should be able to hear the stuff sloshing about when you shake the wheel, even months after applying.