I have to move a Hydra 16 (170 odd kilos up a sandy beach by myself.
I have thin pneumatic tyres and it is hard work.
I understand and believe that the fat tyres are best if you just pay the price. I work one side when the sand gets deep and then the other.
It is worth the effort.
Don't go for the wide yello wheel for sand,, You need to be able to let a bit of air out so the tyre flatten to their widest.
I use the yellow wheels also on another boat and they are only okay.
I have developped a very effective way of using those wheel sets by the way if they cause you trouble.

However.. I found four rubber fenders very easy with my old '59 20 foot Attaunga Attached. Put one under each hull and push and when they almost run out put the other two under..soft sand is easy then.