In-line cooling is an option. You can go from room temp flat product, straight into a filling machine. However, there are plenty of gotchas and limitations. I evaluated the ProCarb units linked above as well as offerings from QuantiPerm last time this topic came up; both seemed good. I got some great guidance from QuantiPerm. https://quantiperm.com/xflowminisurge/ . These units are not cheap.
You will potentially need a lot of cooling capacity to bring liquid down to carbonation temps that quickly. And you need to be running large, frequent batches for this to make sense. Supposedly the inline units consume less co2, but it seemed like a pretty marginal difference in the grand scheme of RTD costs. You also need the right pump (a powerful VFD if memory serves) to deliver the product to the sled at the appropriate flow rate and pressure.
In the end we wound up using brite tanks.