I understand how you feel bro. The houses behind my front neighbours are facing children's playground with lots of trees. The entire row front porch are always full of dried leaves. Everyday I drive pass their houses I feel sorry for them and the idea of using Raven brush like weather seals come into my mind but the weather seals on the market are too small and I dont think you can use it for main gate.
How about getting those floor blower that you can see in public toilet and put it facing your gate. Switch it on 24/7 and let it blows whatever leaves or particles outside your compound. I know it sounds unpractical so just make it a daily rituals to sweeps your car porch. I sweep mine everyday too, it tooks me just five to ten minutes everyday.

Yup.. Ace hardware has mesh netting,

yup and black in colour too

You need some form of netting to prevent leaves from entering the gatre. PVC netting looks cheap and will not last long. You can use galvanized steel or stainless steel netting.

The bottom gap can be covered with a rubber flap inserted into a metal U-channel which can be screwed onto the steel gate.

With our without netting still need to sweep the parking porch. Mine still have leave coming in but from my observation not all coming under the gate some coming in via neighbor. So after blocking the front still leaf coming in. well that is my house.

Now I just sweep once a week. Every alternate week the maid come my place she will wash the floor.

Stainless steel netting if u can afford. Different sizes with different pricing.