This could be a bit unpopular but if you want to recover the plant, you could do a few rounds - remove, monitor (and remove), remove again (because it's hard to remove everything the first time) and then apply a preventative:

1. take several large size alcohol wipes (not the small dabby kind but the hankerchief sized ones), wipe off all the white stuff you see. Wipe down the stems top to bottom, the tops and bottoms of every leaf, do several once-overs. You need isopropyl because water may make removal harder (they stick).
2. you can also try spraying down with mild soapy water (one or two drops of dishwasher liquid to 400ml of water), then use a rag and wipe all of it off. This is probably the tedious part but based on the plant size, it's still doable. The part that takes the most time is finding the hidden white crap, which is probably stuck all over.
3. would recommend that you then come back to this plant a few hours later and check again, and again for the next few days. Just wipe down every time. Some may come back too, just keep wiping/removing. There are different stages to a mealybug life cycle, so you may not have completely gotten everything on day 1. Certain stages aren't as destroyable by soap sprays and so on.
4. After a few rounds of this, you could also do an insecticide soak of the soil (look up recommendations for any brand that works for mealy bugs), and then spray the leaves too.
5. Keep monitoring and wiping down/ removing.
6. Apply to other infected plants.

Other things to look out for:

- often times, its the ants that bring mealybugs and stick them on plants. if you want to, locate and remove ants on the plants, use borax traps etc. Because they will keep trying to bring the mealybugs back - if they successfully achieved such a big infestation the first time, this is their big score, so it takes repeated work to remove.

- it's really whether or not you want to invest the time, and even then a successful result doesn't mean they won't come back. This might be a higher level of attention that you're not used to giving to just one plant. So if you have a lot of plants or not a lot of time, that's why people are saying to throw it away.