Older MacBook getting painfully slow, what actually helps?

Check heat as well. If Activity Monitor shows kernel_task using a lot of CPU, that's usually macOS deliberately slowing things down because the machine is running hot. On a laptop that age the fan and vents are probably full of dust, so a clean-out can make a real difference. Using it on a desk instead of a bed or sofa helps too.

Had a 2017 Air for years, it can still be usable. In order of what actually made a difference for me: 1. Open Activity Monitor, sort by CPU then by Memory. Very often it's one thing (a sync app, an old antivirus, a stuck browser tab) eating everything. Quit it and see. 2. Login items. System Preferences > Users & Groups > Login Items, and remove anything you don't need starting at boot. Also check Safari extensions, a couple of bad ones will slow every page. 3. Get storage under about 70% full. macOS needs free space for swap and caches, and with 8GB of RAM it swaps a lot. 4. If it's still crawling after that, back up and do a clean reinstall of macOS. Years of leftover junk is a real cause of the beach ball and a fresh install is the closest thing to a new laptop. What it won't fix: heavy modern sites in Chrome will always feel slow on that CPU. Safari is lighter on it.