Hi,
Not sure if you have found an alternative yet, but I was recently on the hunt for a similar app because of my own constant horror show with SS - if you haven’t yet, try Simple Inventory. It has the same basic functionality as SS at a fraction of the cost (starts at 2.99 is/mo for manual CSV upload, no max on SKUs. For me, that’s $72 less than what Sucksat-Syncing was charging, and it actually performs the updates faster. Hope that helps.
Oh and the CEO Chris responds pretty quick, and is always willing to assist.