The board will probably make the largest difference. Just carrying it down the beach will be more enjoyable. So I'll say board. Hard to look past a lift 150x though. :) I wouldn't be mad at you if you went that way. Deals on used 170 ha's should also be widely available. So keep an eye out for those.

Hard to gauge your skill level, which would definitely influence my advice here. It sounds like you are on the Lift Surf series, which isn't the greatest pumping foil. If pumping and gliding is your goal, then switch out the foil first. Without knowing your skill I can't say what foil you should switch to, but either way it should be higher aspect. I think switching within the Lift ecosystem makes most sense since you can reuse the mast, and their wings all carry some similar carryover ride characteristics.

I'm larger than you (about 80kg). Started on a 90L board (after my first couple sessions on a larger board) and the Lift 250 HA. I was comfortably mowing the lawn, gybing and doing some basic pumping on that setup. I wanted something faster, so I switched to the Lift 200 HA, which was better than the 250 in every respect, although it wasn't a dramatic improvement. After about a year on that setup, I switched to the Takuma 1095 and 1440 (still on 90L board), which was much more lively and fun - this was a dramatic improvement in terms of glide, pump and maneuverability.

Shortly thereafter, I sized down to a 60L board, which was also a dramatic improvement. Definitely harder to get up on - took several sessions to figure out new starting technique, and my low end was slightly worse. I literally never used the 90L after I sized down to the 60L board.

Whereas the foil was a dramatic improvement in terms of speed, glide and maneuverability, the board was a dramatic improvement in terms of responsiveness and "feel of the foil". The smaller board just feels sportier.

You also need to consider whether you are building a quiver and will keep the old gear for use in some conditions, or if you are selling and need something that will cover all conditions.