Nobody mentions this part: a gimbal is a system, not a tool. The sticker price doesn't include the balancing time (10–20 minutes per lens/camera combo change), the follow-focus or wireless monitor you'll eventually want, spare batteries, and the fact that most gimbals have a payload ceiling that quietly excludes your next camera upgrade. A slider has none of this — it's the same tool on day one and day 1,000.
A dolly, meanwhile, is the one that gets the least use per dollar for a solo shooter: it genuinely needs a second person to push it smoothly while you operate, or a motor add-on that erases the cost advantage over a gimbal. If you work alone most of the time, that alone should drop dolly to last on your list.