Hi fellow Ness fans! This guy has been my main (or co-main) since 1999 and he seems better than ever in Ultimate. My ground game usually does pretty well, but here's my big issue with Ness:
Whenever I'm hit off the stage in any capacity, I really struggle to not get smacked around (or into the blast zone). Even ignoring Ness's recovery issues, whenever I'm simply high above the stage and trying to land, the opponent has a huge advantage and can usually get a solid hit in, or at least have some serious stage control once I touch ground. Ness's floaty weight and lack of a reliable dair or some sort of downward attack really make me feel like a sitting duck above the stage. If they chase with an aerial, I can usually air-dodge okay, but I tend to lag a lot when landing. What are his best options when I've got an aggressive opponent ready to up-smash me when I'm coming down?
This is just kind of a Ness thing unfortunately: being a floaty boy, if you airdodge in the air, you are potentially stuck in the air
for ever unable to do anything. I find mixing up your aerial drift helps a lot. Like make out that you're drifting left and then when they start committing to covering the left, start drifting right instead, maybe with an airdodge. Those kind of mixups help a tonne.
You can throw out a nair and attempt to trade positively but obviously evaluate the risk-reward here. If you're gonna die and they're not, don't do it.
And sometimes just airdodging to a platform, or the ledge, can be a safe bet.
A cute little trick you can do with PSI Magnet in this game is to double jump and quickly PSI Magnet and it pushes you horizontally a fair way quite quickly. You can use this to get to the other side of the opponent and BAir them, for example, or otherwise just rapidly move to dodge a hit without pulling the trigger on the risky airdodge.
Sometimes it's best to airdodge a strong hit and just accept that you will get hit by something else, but be safe in the knowledge that getting hit by the first attack would have been way worse than getting hit by the second. e.g. air dodge the up smash and just accept that you might get dash attacked for it. Better to get hit by a non-lethal dash attack and have another stab at resetting neutral, rather than just straight up losing your stock to up smash, right?
And sometimes you just want to land without pressing any buttons at all. Don't give em anything to punish if you don't have to.
Hope that gives you some ideas!