Firefox doesn’t actually load all tabs on startup (only the selected one) and it allows you to unload tabs, so you can be fairly efficient about it.

That said, it can easily use a couple dozen GiB after an intense research session or a few weeks of regular usage but that’s manageable with even just 32G and, as I said, you can always unload tabs (or restart; effectively unloading all tabs) to reduce usage at any point.