Nope, that'll make you "zig" when you should've "zagged".
I heard one time that if you put large draw items on the bottom it can cause excessive heat to the bus bar and lead to failure over time to the whole panel.
That idea leads to a conclusion, which is that the breakers should be down the panel largest first, with the 2 largest breakers opposite each other. However, this is nonsense.
What is definitely not nonsense is "stab limits". The stab is the little blade or bar that the breaker clips onto, and serves the breaker on the left and the breaker on the right. We can tell stab limits aren't nonsense because they're stated right on the panel labeling, and must be followed per NEC 110.3(B).
So you can see: there's an inherent conflict between the "pop logic" of bunching big breakers at the top, vs UL/Code requirements of stab limits. Your 100A would be opposite another large breaker of 30-60A, and you'd have 130-160A on that bus stab.
The best thing to put opposite a 100A breaker is a generator interlock or a surge suppressor. In generator mode, the stab cannot exceed generator output x 2 even if it was all going to the garage. After that, lightly-used circuits which for some reason need to be dedicated, such as a 1 amp fridge (common sense) or a 6 amp gas furnace (Code).
Note that the loads in the subpanel need to be included in the main panel's NEC 220.82 Load Calculation. If this is for EV charging, there's a "50A misconception" which is bonkers overkill for home needs. Technology Connections has a first rate video on the topic.