I built a very simple, DIY drip system from home Depot parts that has worked well, described here: Slow deep watering options for fruit trees - #12 by slartibartfast
I used drip line with inline emitters, 1 gal/hr/emitter. Generally 5 emitters per tree to spread out the water, but these trees are in the ground, not containers. 3 seems fine for a container. I’m only running the system for 45 min to an hour, once or twice per week. I figure having more emitters and a shorter runtime makes clogs or other issues less likely.