Have you tried the Modifying a Category Savings workflow?
I think you’ve got everything setup properly (with the categories set to track and the budgets set at the minimum). I recommend that at the end of the month you just enter a negative savings adjustment into the salary category and then positive savings adjustments to redistribute that into categories you want to use it in. This is essentially the same thing that was happening with the automated “rollover-to” in the old budget.
The TCS add-on will make the change in the Budget History sheet and no “manual transactions” are required.
Or you can just leave the surplus in your growing salary category until you’re ready to spend it.
Good luck.