used to dread rebalancing day, now it runs overnight

About $47k taxable (6 stocks, 2 ETFs), 401k with target date fund, Roth at 80/20 VTI/VXUS. Rebalancing used to take a full afternoon every quarter because of the tax lots in taxable. Few weeks back I set up a small job on a cloud machine. Pulls holdings, runs drift calcs, spits out trades with estimated tax impact. Runs overnight. The thing that got me: it sorts every lot by holding period and builds the sell list clearing long term gains first. Flagged one lot that was 3 days from crossing one