The double action hand pumps that you can get for blowing up paddling pools etc. make great tubeless inflators to seat the tyre, you just need a bit of silicone tubing to put over the nozzle of the pump and the valve, you need to have the valve core removed otherwise it blocks the tubing.

So does a bog standard track pump. Which I already have.

I recently used a 5l garden sprayer as a tubeless inflator & it worked a treat.

Benefits were it came with a nice trigger so you could control the flow & you could get a decent sized store of compressed air to start with. Worked much better than a track pump.

I can see the high volume of a pump like the OP pictured working better than a normal track pump.

Mine didn’t, until the tyre was seated with this.