I have the Mavic Air 2s. Used it for boating and it does great but with a few downsides. Almost crashed it due to no side sensors. Its not easy to hand catch as there is no landing gear.

I am wondering is going backwards in tech is going forward when it comes to boating. The Phantom is heavier, so better in high winds and has landing gear which might make it easier to hand catch.

Any thoughts?

I would say the Phantom is better if wanted for landing on the boat because of the landing gear you can easily hand catch and Yes, as you mentioned a much heavier drone to handle winds.

Yes and no.

If you have a lot of wires, a smaller drone could be better.

Phantom4 though has atti-mode without hacking, which makes it much easier to launch and hand catch if the boat is moving.

My mavic2 handles wind better than phantom4. I wasn't happy with air2 though.

This one -

I think In steady winds the mass of the drone does not affect the drones ability to fight the wind, all that matters is the maximum air speed and that's a question of thrust and max drone tilt.
Case in point, the Mini 2 is, or is considered to be, better in wind than than Mavic Mini yet the Mavic Mini is the heavier drone.
Where mass/inertia may come in to play is, I believe, in variable winds and there, the more mass, the 'smoother' the flight.

With regards to Phantom vs Mavic, the Phantoms have the disadvantage that they are generally older and batteries may become a problem.
In wind I much prefer to hand catch a Phantom rather than a 'naked' Mavic.
That said, there are attachable handles for some of the Mavics. Google "handle for mavic 2 pro". Positioning might be critical as they might interfer with the bottom sensors if incorrectly placed. I have not tried one and have no intention of trying one and I have no opinion concerning them, I am merely presenting possiblilites.

The Phantom is heavier, so better in high winds.
This is a common myth but it's not true.
The weight of the drone doesn't affect it's ability to deal with wind when flying.

Hello there waynepj3gmail.com. Good day and thank you for reaching out. I hope that our fellow DJI co pilots can give our some recommendations with regards to this matter. Just a reminder that when flying above the water, the vision positioning function will turn off automatically and only the GPS and barometer are used for positioning, if affected by the accuracy range, and an accident might happen. In addition I will also post a DJI Forum thread on How to Fly Safely Over Water. Thank you.

https://forum.dji.com/thread-181878-1-1.html

DJI Stephen Posted at 4-6 19:03
Hello there waynepj3gmail.com. Good day and thank you for reaching out. I hope that our fellow DJI co pilots can give our some recommendations with regards to this matter. Just a reminder that when flying above the water, the vision positioning function will turn off automatically and only the GPS and barometer are used for positioning, if affected by the accuracy range, and an accident might happen. In addition I will also post a DJI Forum thread on How to Fly Safely Over Water. Thank you.

https://forum.dji.com/thread-181878-1-1.html

Just a reminder that when flying above the water, the vision positioning function will turn off automatically
The recorded flight data doesn't support this claim.
Vision positioning might not work properly, but it's still active.

I have the Air 2S and also live on a large boat.  So for that reason I always launch/recover via hand.  Took some practice but now just comes natural.  I'd say practice this a lot on land before you give it a try from a boat to build up your skills and confidence.

Mobilehomer Posted at 4-6 12:05
This one - https://youtu.be/3wkCcP_UrAo

That SplashDrone is quite interesting.